Because its an entire industry that is outside the western influence and thereby caters to a lot of the tastes that the West is deliberately trying to destroy. So it provides a form of escapism well outside the stress filled minefield that is most of the rest of media that is filled with subversive politics and manipulation.

Even a Nazi sometimes wants to just laugh at cute girls being with, without having to worry she will have a black boyfriend or some shit.

Its only anime so often because that's just the only major source of it. Comic books had similar appeal and power back in the day, before they became infested and only about capeshit. Same with video games.