That’s actually some interesting sociology. How would you go about having an intelligent agent/actor maintain loyalty to his group if someone tries to “reason” with him?

Well, if he has been taught to dismiss it outright without considering the argument with a pithy “I don’t want to listen to your talking points” (the wording doesn’t matter, there are several variations), then he will remain loyal because he dismisses it without considering the argument but also without completely wrecking his ability to sometimes act intelligently and consider arguments (good arguments, the ones your group makes obviously).

Without it, the other side can win. Either one of their arguments is logical enough to convert him, or they saddle him with so many arguments that won’t work but that wastes his time as he reasons his way through them (a sort of denial of service attack on the brain).

We all believe that we’re intelligent and rational, but we’re just dumb monkeys who are incapable of rationality. None of you are capable of considering arguments unless first they have been vetted by your ingroup.

This is the mentality at work, and also why you are punished for your non-conformity. Conform or be punished pimento.