Is there any worst combination than stupidity and righteousness?

It seems throughout the history of mankind the most effective way to control the mindset of a popluation is to appeal to the dumbest and then give them a sense of worth for "being right" Once they're on the hook they can't be convinced otherwise. First because they're too stupid to see any other sides of an issue. And because they are RIGHT and therefore you are WRONG. Is there another combination that is used in such a way?