I think you're reading into it way too much. I only see it as an innocent bit of fun, especially in this game. I'll take teabagging over teamkilling any day.
One is just unsportsmanlike, the other I actually find offensive. When someone team kills, they are actively demonstrating that they have complete disregard for the time and entertainment of the other 9 people in the lobby, it's utterly inconsiderate, a horrible thing to do.
I actually removed a guy from my friends list who team killed one of us 'as a joke'. Not interested in playing with someone like that. Meanwhile, some people on my friends list do teabag, and while I consider it unsportsmanlike, most of us just take the piss out of them when they do it. It's childish and makes me cringe, but it doesn't make me hate the person doing it, like teamkilling does.
So I think saying you'd take tea bagging over team killing is an obvious conclusion, but it doesn't make tea bagging any less juvenile. It's like taunting in fighting games (also generally frowned upon), except it also features a rape reference... lovely.