Of course the problem with mental corruption is that it doesn't really respect borders. There's a short step from Farrakhanesque numerology to believing in little green men. Likewise, a group conditioned to, at once, believe that they are "the greatest people that have ever trod this earth," that the stars and bars actually stand for barbecue, NASCAR and rugged individualism, that the Civil War had nothing to do with slavery, are exactly the sort of people conditioned to believe that man once hunted dinosaurs, that Obama is (all at once) a radical Christian and a closet Muslim, that global warming is a liberal hoax, that a neurogical diagnoses can be done via video-tape. To be sure, history is littered with smart, well-read racists.But they weren't any smarter for it.
One doesn't need to have ever been to the Southern US to know exactly what he is talking about, he is talking about the desire, even amongst intelligent people, to use mental short-cuts whereby all the arguments one is inclined to disagree with the most can be waved into bins where they require no more attention. Intelligence doesn't make you immune to laziness, in fact it can often allow people to invent new ways to deceive themselves.