I can offer a few answers. Here's one: People who reject new ideas in favor of what they previously learned do poorly in college. Throughout education we learn things that contradict previous lessons, and its an essential part of being a functional human to adapt as facts change.

Maybe people who stand up every class in biology to tell everyone they don't believe in evolution aren't good students. Not every conservative does this, to be clear, but I know first hand that some do and that sometimes they were convinced their failing the class was due to liberal teacher bias.

Says who? My college grades were fine and since I switched to an Aviation college I've been going with flying colors.