Tumblr i the only other real leftist space I think. You could maybe put baseline social media is somewhat leftist, tik tok, instagram, snapchat, most of those have a leftist lean, primarily because they trend younger. Your general use social media is going to have a left/right lean based on age demographics. That’s just the lean those general social medias are going to have.
Password expirations are bad practice and counter-intuitive to what the ultimate goal is. If you have a long, complex, unique password for a system that is not used anywhere else and is stored in a secure password manager that has not been compromised, changing that password is worse than meaningless, it’s actively harmful. No one in the IT or Security field should be advocating for password expirations at this stage of the game. Unfortunately everyone is forced into the practice to comply with PCI regulations that have not kept up with changes in security.
It basically has to skew older, probably 25 to 30+ The vast majority of those younger are going to be on tiktok, sc, insta, or something like discord. Lemmy will be considered more “left” overall than even reddit was. There will be of course bad instances, but i think pressure to defederate from them overall will be strong, especially when the “free speech” instances start having difficult legal questions thrown at them when their users inevitably start saying the quiet part out loud.