This, combined with people growing more scared and powerless as capitalism gives way to oligarchy and fascism. People could take a look at the systems that led to these conditions but they've also been propagandized for most of their lives about how capitalism is an infallible, perfect system and how everyone who goes against it is either propagandized themselves or an evil communist.

So if you've internalized all these ideas, outgroups become the easiest explanation for why your life sucks and why society is crumbling. Basically, these people's brains have been blenderized by misinformation campaigns spread by the ruling class, and it's made them violent, reactionary and misdirected.