That lots of fascists and other reactionaries appear “dumb,” in that their views and positions have no relationship with historical/biological/sociological reality, doesn’t mean they have no political savvy. If anything that’s what makes them a danger, not having to remain grounded in the rules of the game that is rational public discourse. They’ve cottoned to the fact that liberal society will let them play that game without fuss anyway, even if their contribution is “there is a race war between white people and the Jews and we’ll stop at nothing to see our side win.”
I was talking with a group a few weeks ago about how fascist ideology (and right-wing ideology more broadly) is deliberately anti-rational – it appeals to cults of action and war, mythical depictions of a glorious past, and emotional manipulation through patriarchal affirmations and racial scapegoating. And then someone replied by saying “well, I agree that fascism is a dumb ideology,” which is precisely the opposite of what I was saying. Some of its adherents might be dumb but as a political strategy, it is very, very clever.
That’s the threat they pose. There are some who will actually be dumb saps and some who will just be playing the part to sneak their way into the mainstream, as they have already done; either way it’s to our detriment not to take them seriously, or to not take the steps to dismantle even the potential for them to gain any more ground than they have.