How do people in this day in age become nazis/neonazies sexist or even incels when there is so much knowledge against it? Do they get anything out of being that way?
This video is actually shockingly relevant right now, and does go through (some of) the 'hows' and 'whys'.
Remember that tradwife/incel/etc shit is all just fascism boiled down into specifics. The Nazi's sent women who wouldn't marry to camps just as easily as Jewish people, gypsies, etc. We think of the Fascist movement as specifically anti-Jewish people, maybe throw in some gay people/etc, but Unionists, Communists, Socialists, and Women were targeted as well.
The reason it works is because it offers easy answers, and the average person has been made to be so lazy they'll accept what they're told, especially if they're told everyone else is doing it. They aren't a Nazi, they're part of the Nazi's.
We also have a huge backlog of emotional baggage for men post the 1980's. At some point we all accepted that men wouldn't show any emotions except anger, rage, frustration, etc, and then kept doubling down on it. Now you have groups of young men fed directly into a pipeline of Facebook/Youtube/whatever platform that spoon feeds them fascist garbage. Why? Because it makes them tame and easier to control. You notice fascists aren't out there killing rich people, they're killing minorities? That's by design, because the wealthy know they're fucked if young men turn that rage against them, the real perpetrators of said poor people's suffering.
The wealthy love fascism, it gives them everything they want. They don't see the poor people below them as human, so it's all just a giant menagerie to them so they can have their Line Go Up Faster than the other rich people.