I don't think Fox viewers 'believe' any of it. I think they're just racist, misogynistic assholes who think that way that use Fox as the "See? I saw it on the news" excuse for being a racist, misogynistic asshole.
Not sure if that comes across clearly, but there it is.
It's like all the January 6th morons: people say that Trump made them.
He didn't. They were there all along. He just emboldened them to come out of the closet by poking them with a stick.
Fox News is the same. They play on what's already there.