We really need to step out of the idea that radicalization only happens to people who are somehow slow or uneducated. It might make you more likely to fall for it, but cognitive ability and education will not mean you will not end up there as well. Issue with the anti-intellectualism of the alt-right is not if someone themselves has education but if they are willing to listen to other people who do. If no one is an expert for example racist ideas of the alt-right about biological differences can't be refuted. Which is probably partially where it comes from times quite a lot.
Everyone likes to think they have cognitive ability. If we just think radicalization happens only to stupid people, and you are not stupid, getting a person de-radicalized is going to be a lot harder. Thinking that we as people with cognitive ability can't be radicalized will also make it easier to fall for it because you can't be radicalized.
Instead of intelligence or education, we should focus on the trifecta of vulnerability, marginalization, and othering. That's a better predictor.
(And no, I do not actually disagree about the ideas being idiocy, just that falling for them are not just for idiots)