>>385310people will recc you political things but at this point in your questioning i'd look more towards psychology, developmental psychology maybe and stuff about cults (from people who know… psychology). Cause what you're asking is basically what fucking short circuits in their brain to cause this retardation.
part of it is control of language, and people don't question it. Keep in mind people tend to be pretty bad at moving among thoughts "vertically" or "turning the mind", like extracting themselves from their box of how things relate to each other, and asking questions about the very material of it. So someone says "commies rule the media, they oppress us!!" then if you say "i'm a commie, i oppose oppression by the elites" they will think "that person is a lying asshole trying to trick us". Because they havent questioned that original idea. The evil part is when it's not explicit, so we have just a single word - "communist" (or something), and in their mind it means all kinds of things, e.g. someone who wants to make you work longer, someone who wants to take your rights, someone who wants to make the government meaner, someone who wants you to be poorer.
Also part of it is just tribalism, they have their group, and their group thinks a certain way, and it can be very hard to counter this. They might just never feel a need to think about it any further than "fuck leftists".
also part of it could be like sunk cost mentality. Recently I saw this super cringe scene in some new superhero show about captain america, and i guess some black guy takes his place because he goes missing, and anyways this old black dude is like "why are you wearing those colors? why are you accepting yourself as a defender of america? you're black, you know what they did to us?", and he's like "my ancestors didn't die and sweat working this land just for me to give it up". This is exactly the kind of thinking that I mean - it doesnt matter how shit things are, because you spent a lot of effort surviving in this shit, so why would you want to change it now?
It's retardation, and it's specific and reproducible retardation. Look to the science of retards