> If you conclude that factor is "they're stupid" or "they're evil", then you haven't found it.

You seem to be dismissing those explanations simply because you don't like them and you reject the idea that it could be true of so many people. But you aren't actually providing any evidence against these explanations. Simply exaggerating them to the point that you think they can be dismissed as unreal doesn't work. There's a mountain of evidence that large numbers of people can and will passively tolerate evil policies and continue to vote for their proponents on the basis of issues they care more about. There's plenty of evidence that large numbers of people can and will vote for candidates who are making empty promises to them. There's plenty of evidence that large numbers of people can and will reject sound information about reality when it conflicts with dearly held beliefs.

Nobody (except perhaps you) is trying to say that Trump's success boils down entirely to those two factors that can be described as "evil" and "stupid" when taken to the extreme. But it's quite reasonable to conclude that those are indeed very important factors to his success and support.