I haven't compiled any data relating rudeness to karma, and thus only have my imperfect recollection of prior comments to draw on, but I can certainly see your point here. I doubt, however, that an unpopular opinion or argument would benefit from rudeness if the post is initially well formed. I would expect rudeness to amplify polarization, thereby benefiting popular arguments and high status posters, and politeness to mitigate it. Would you be willing to provide me with some examples for or against this expectation from your observations?