Same thing any "in group" feeds on: self esteem. If you feel powerless, or worthless, or rudderless, any group that makes you feel powerful, valuable, and effective is going to be very appealing. Conservatives (read: fascists) prey on this. They make it seem like joining them is brave, and important. And since their followers lack identity and purpose, their self worth becomes entangled with [in group], be it closeted fascism such as the American GOP, or flaming such as Q/proud boys/whatever. And since their identity and value depends on the perpetuation and proliferation of their in group, they willingly accept lies and falsehood. Pretty easy to gaslight someone who's encouraging it.

Then when they wear their symbols of hate, or make shocking claims, or in anyway troll and grief society, up to and including dismantling democracy, they get a reaction. They've exerted their will on the world around them, and as such they feel powerful. The insidious bit is, even if the good guys win, with all their high falutin factual arguments and social programs, it just makes these sad people angier and feel worthless again. So they go right back to their pimps for some more sweet lies and marching orders.