Rove's comment reflects polls saying that the more educated people are, the less likely they're going to vote republican. The basic reason behind this is that educated people tend to have a broader world view and get informed about current events from more than just one or two sources (eg. Fox news doesn't have the echo chamber all to itself). A republican's diet of "fear and hate the 'other'" doesn't work so well on someone who's innoculated against it by education.
