This apparent difference in the power of the arguments can confuse naive open-minded people (like myself a few days ago).
Whoa, damn, you mean to say you recanted? That's cool, I guess. Now join me in my meta-meta-meta-contrarian ivory tower; you're smarter and more diligent than me. Although less interested in politics, I guess.
I've sort of gone back on one specific piece of evidence, which was that contrarians on some issues tend to have much stronger arguments, and therefor are probably right.
Yvain explained that quite well by noting that believers of popular belief have no incentive to seriously engage contrarians, lest they "legitimize" them or appear like they were taking them seriously. It is much more individually beneficial to point and laugh.
An extension of that, though is that you can get signalling absurdity arms-races that cause the mainstream position to be...
As Multiheaded added, "Personal is Political" stuff like gender relations, etc also may belong here.