For me, there are several very different good reasons. I write Them down in order they come to my mind not from imoortant to less important or vice versa.

1. i dont want to be judged before met in Person

What do companies do before they hire you, banks that you ask for money etc. They look you up in the net before they meet you. Think they know you. No Chance to present yourself as you want it. Yes you can polish your social media but not all the hidden profiles they made of you…

2. stalking

i once studied in a different country. Had 3 dates with someone i only realized then is weird and kindly ended dating. Then this person was stalking me for a year and only stopped thx to the police intervening after a lot of efford from my side. Luckily the person only had my email and phone contact and new which city I came from. I was SO glad Ive never been much on social media and stuff… Cause this person would have come to my hometown, waiting in front of my university or whatever - even wrote so. But couldn’t find out. Most of my friends back then had their address / favorite bars / university courses favorites places and everythign in the net. I was so scared back then i would have changed my entire life to be sure not to Meet this Person. Luckily i didnt have to cause my life was private. If you think stalking is very rare and you will not be affected look up the numbers. Its horryfying. For woman especially but also men. People dont talk about it but During that time when speaking to friends i suddenly knew 5 other people who had to deal with it already. Also nowadays these apps exist were you can take a picture of someone and search for that face in the Internet… A stranger can do that and find all your photos/ social media etc and be there in your favorite bar every nicht… Scary.

3. data is power.

On the " i have nothing to hide" thing. Think of Google maps. They dont care where you go at all but by knowing where everyone goes they can predict traffic, give u alternative routes and theoretically they could also causetrafficb jams… :D while maps is useful they can do the same with any information. they are not interested in your political views but by knowing everyones political views they can predict and also direct them. This isnt theoretical its used in elections already. There was a scandal a few years ago about brexit ithinlk.

4. i like to have control about myself

Sometimes i might even agree to share some data for something else but i am forced to it all the time and i have no control whats done with the data to whom its sold next etc. But its still my personal data …

5. governments/ laws change

Well i am german, actually from an eastgerman family. If my family teached me anything its that political systems can change very easily. My greatgrandparents, my grandparents, my Parents and i grew up in 4 different political systems, well actually 5 :D. Every system of those had different views of who is good and Bad And it was better they dont know everything about you…

Just because you feel you may have nothing to hide now, doesnt mean that information could be very worth hiding in the future.

Governments change.

Laws change.

Dictators, autocrats, police states, abhors dissent. Free thought and peace of mind is what you’re protecting.

(I am not an expert, just a hobby self-hoster)

Think of how police obtain information about people. They usually do an investigation involving questioning and warrants to receive records and put together a case. They must obtain consent from someone or get a warrant from a judge to search records.

Or, they could just buy info from a data broker and obtain a massive amount of information about someone.

Imagine if every company has this info and can tie it in to your daily life. Google probably has your data location history and can see exactly what routes you’ve taken lately. They can use that information, with timestamps, to estimate your speed. What if they sold it to your car insurance company, who then uses it to raise your rates because you are labeled as a speeder?

What if your purchase history is sold to your health insurance provider and they raise your deductible because most of your food purchases are at unhealthy fast food joints?

Now, with AI being shoved into every nook and cranny in the tech we use, AI can quickly get a profile on you if it is fed your chat history. Even your own voice is not safe if it can be accessed by AI. This can be used to emulate you - Interests, chats, knowledge, sound. People could use this to steal your identity or access accounts.

I am/was in the same boat as you: For a long time, I just didn’t care that I was giving away a bunch of information in return for convenience, and didn’t get why people cared so much.

I don’t really know what triggered it, but at some point I became painfully aware that the only goal these companies have is to squeeze every possible penny out of selling me. I started noticing that the stuff they ask you to confirm is 95% stuff they want because they can sell it, or use it to get you hooked to their service, and 5% (at best) stuff they need to make the service good for you.

This triggered a change in my perspective: Now it pretty much makes me sick to my stomach to think about all the companies that are drooling over me, trying to make a buck by getting me to click something I’m not actually interested in, or don’t actually need.

These people have a vested interest in manipulating me, and by giving them my data, I’m giving them the tools to do it. I don’t want to be manipulated or sold as a product: That’s what made me start caring about protecting my data.

Let me tell you a story. Many years ago I worked for big banks and insurance companies. One day I was tasked with a project. It was an amazing, from the tech point of view, project. It was something like this: a user navigates to a bank website looking for information about some product. The website presents the user a simple contact form - first name, last name, phone number and/or email. Based on provided data bank would use it to update user data (if there was no official account it would update the “ghost” account, aka “I know about you, but you don’t know about me”). Next the bank would scrape all publicly available social media accounts and build the “hidden” profile (I’ll get to this later). Based on all that data, user would be assigned a score based on which all future interaction with a bank would be determined. For a regular person this would mean that “I’m sorry but according to our system we cannot give you a loan”.

Now, about the “hidden” profile. It’s a thing that all big companies (including banks and insurance companies) hold. It’s all the data collected from all publicly available profiles (and sometimes from the shady sites), used to create a profile that’s not visible to a frontline workers and it’s referenced as a “system decided based on your data”.

Now, to make this more scary. This happened 10-15 years ago. Way before the so called AI. Imagine how much more data those companies have about you in today’s world and how good they are in processing it.

You have asked the most important question in this topic. Privacy and security only have meaning when you develop a threat model or encounter a threat. With digital security it is usually pretty straightforward in that you don’t want anyone else controlling your computer or phone and using it for their own ends. And a lapse in digital security can ruin attempts to secure privacy.

Privacy is where threat models should be developed so that you (1) don’t waste time worrying about and working around nonexistent threats and (2) can think holistically about a given threat and not believe in a false means of privacy.

For example, if you are of a marginalized community, closeted, and in a very unsafe living situation, your main threat model might be getting doxxed and outed. To prevent this you should ensure that there is zero to no information that would link your real identity to an online identity and you should roll accounts to ensure small slipups can’t be correlated. VPNs probably don’t help in this threat model but they don’t hurt either. A private browser does nothing in this situation. Securing your phone and not leaving it unlocked anywhere is good for this situation (sometimes privacy isn’t really about tech but behavior). Using strong passwords that can’t be guessed helps with this situation. Making a plan to move to a safe living situation so you can be out will resolve the threat entirely, though it may mean needing to think about new ones.

Notice that the government was not in this threat model and that it was more about violence towards the marginalized. Cis white guy techbros generally have nothing to worry about re: infosec and are just being enthusiasts or LARPers. Nobody is showing up at their house with a gun and the feds are not going to arrest you for having the most “centrist” political takes and actions available. The people that need to project themselves are those facing overt targeted marginslization or who take political action that the government wants to, or would eventually want to, suppress. For example, the US government labelled anti-apartheid groups as terrorist organizations and intimidated or jailed those they could identify. It has a habit of doing this to any advocacy groups that gain steam and actually pose a political threat to their opponents.

Even if you don’t have a threat model, though, having good digital hygiene is useful in case one develops in the future. You may currently do political work that seems safe, and it is because it is not perceived as a threat. Let’s say you help organize unions. But there have been times where organizing unions would mean you’re targeted by the government and hired thugs and those times can easily return. If they have compiled a database of likely union sympathizers, will your name be in there? Maybe that’s a risk that you just take. But maybe you should use good privacy practices so that you can go underground when needed.

The latter applies to the threatless cis white techbro “centrists”. Such an individually may someday change politically or in their gender identity and having good practices would then pay off.

In addition to everythong everyone has said, one major thing that people often don’t think about privacy is how it relates to enshittification.

Modern software services try to optimize everything to make as much money as possible. Everything is a/b tested, and whatever increases some arbitrary metric is what gets released.

They do this by tracking a ton of metrics about how you interact with everything. I know where I work we collect data about every time you click on anything, how long you hover over buttons, etc.

Name, address, GPS localisation data, habits (like apps you often use, moments you use one device or another), gender, search terms in search engines, open web pages on a web browser, connection (other person you know), the work you do and where you work.

All kinds of things, really.

The usage is mostly advertising or identity theft.

I’m probably gonna mess this quote up, but I thought it was brilliant:

“Privacy is essential to security, and shitty people feel entitled to take that away from you.”

You can’t be secure in your dealings or operate on equal footing (economically speaking, as others here have pointed out) without a measure of privacy.

There was a jogging app known as Strava that posted an image on their Twitter that was a heatmap of all the jogging activities of all of their users. Their idea was just to show how popular their app was by showing the entire world lit up. Twitter users were able to locate secret US military bases on that data alone. Turns out nobody jogs in circles in the middle of the desert except GIs.

Recently a group of Harvard students did a demo where they used Meta’s camera glasses and a chain of commercial programs and products to find out people’s names, address, workplaces, and family based only on their facial data.

These are just two examples off the top of my head. Essentially, the more data someone can accumulate, the more info can be analyzed from it. With things like AI tools, that analysis is incredibly fast even with huge datasets.

SSRN is a kind of vast warehouse of academic papers, and one of the most excited cited and well-read ones is called “I’ve got nothing to hide and other misunderstandings of privacy.”

The essence of the idea is that privacy is about more than just hiding bad things. It’s about how imbalances in access to information can be used to manipulate you. Seemingly innocuous bits of information can be combined to reveal important things. And there are often subtle and invisible harms that are systematic in nature, enabling surveillance state institutions to use them to exercise greater amounts of control in anti-democratic ways, and it can create chilling effects on behavior and free speech.

https://papers.ssrn.com/sol3/papers.cfm?abstract_id=998565

Privacy is important because it gives you control over your life; details, info, thoughts, emotions…

I recently met a guy out of town at a trade show. We were both in the same show, grabbing some snacks, and I complimented his hat. We started talking, a little this, a little that. Eventually we parted ways. On the outro we introduced ourselves by first name only, more as a BTW side note because we might run into each other again. Why am I telling this story?

Because I forgot his name almost instantly and really only remember his hat. I know nothing about the guy. He knows nothing about me. But wouldn’t it be weird if I didn’t just remember his first name, but I knew his last name too? Where he lived, worked, shopped for groceries, sexual orientation, he last time he ordered pizza and what toppings were on it, how he voted last election, etc… If I knew all that about him, I could have a much more in depth conversation with him. And even if I had no mal intent and simply wanted to give him better experiences in life…that’s not my decision to make. He didn’t ask for that. And it’s freaking weird.

But that’s what has been made normal in our lives. Privacy helps keep your life…well, private.

Then the rabbit hole goes deep on nefarious uses. And it’s not “its possible” to do this, but rather “it’s being done” (with absolutely no doubt or argument).

The same reason why you have curtains over your windows, so random people cant peek into your private life.

I feel like being spied on on the Internet is kind of like having a camera in your bathroom.

Sure they promise they’re only going to point it at the sink and just make sure that you’re engaging in proper toothbrushing habits.

Sure.

But they’ll set it at the point where the mirror shows the shower and the toilet and they’ve got smell detectors in there to determine how much food you’ve eaten and how well your digesting it and there’s a sensor in the toilet to check the content of your urine and then if you drink too much they’re going to tell your boss that you’ve been drinking because they detected the alcohol that your body flushed out in your urine when you peed.

And you have no control over who gets to see what’s going on in your bathroom.

It is morally wrong and psychologically oppressing to be spied upon.

And the powers that be are so focused on the benefits it gives them that they do not care about the negatives that affect us.

Why do you need curtains on your windows?

To make sure the whole world isn’t just a window for the HR department. I can have “dissident” views, or just talk trash with my friends, and not get fired since it wasn’t at the office.

To make sure real dissidents (from totalitarian countries) can express their political views.

So a lady can send her husband feet pics without some secret agent spy gawking at them too.

So I can share my family’s secret BBQ sauce recipe with my cousin without Arby’s stealing it (they have eyes everywhere).

But these are all specific things. The truth is that we simply cannot trust institutions with all our data. I don’t need a reason for privacy. They need a reason to have my info. Security is a legit reason to seek citizens’ info, generally, but you should need a specific security-related reason to access a specific person’s data.