At least on LW, I think the more controversial a submission is, the less the poster can afford to be rude. It seems to me that rudeness is generally a Karma loser here. I've even seen Eliezer downvoted hard for rudeness.

Rudeness can still be a useful strategy for shutting down low-status people, however.

Karma winning strategies include adding footnotes or lots of links (even if they are low-quality or tangential). If you go to the trouble of adding an unnecessary graph or two, that helps as well.