But I took our working definition of crackpot and bunk to exclude such people. We're asking about a particular kind of being wrong: being wrong and unpopular.

Fair enough, if we define "crackpot" as necessarily unpopular. However, what primarily comes to my mind when I hear this word is the warlike emotional state that renders one incapable of changing one's mind, which I described in the above comment. If people like that manage to grab positions of power in the academia and don the cloak of respectability, I still think that they share more relevant similarity with various scorned crackpot contrarians than with people whose mainstream respectability is well earned.

I think a good test for a crackpot vs. an ordinary mistaken contrarian would be how this individual would behave if the power relations were suddenly reversed, and the mainstream and contrarian views changed places. A crackpot would not hesitate to use his power to extirpate the views he dislikes with all means available, whereas an non-crackpot contrarian would show at least some respect for his (now contrarian) opponents.