Well, those are a little different, in that those terms are only considered insulting when they’re used to imply that somebody is gay. Saying that a straight guy likes to eat pussy isn’t much of an insult, because duh. Saying a straight guy like to suck dick is an insult because it’s saying that the guy isn’t really straight.
“Teabagger” isn’t really used the same way. Outside of the political party, nobody’s throwing it around as an insult, like, “Hey, you dumb teabagger!” To the extent that there’s an element of homophobia attached to the term, its mostly by association: the sort of people who like to teabag other players in games tend to also be the sort of player who uses homophobic slurs. And, of course, part of the “insult” in being teabagged is the idea that you were forced into doing something gay.
But I don’t think that association carries over to the term’s use to describe (and belittle) members of the political movement. In that usage, the intent is not to imply the subject is gay, but rather, imply that the subject is old and out-of-touch, because at one point they unknowingly used a sexual term as a self-descriptor.
Maybe your friends are just fond of homophobic jokes. That would be a more understandable source of the confusion, rather than inferring that straight people use the term in only a certain way.
Sounds like you associate with some boring stick in the mud types. And for gods sake, make sure my wife doesn’t hear that only gays are associated with stuff like teabaggery…it will take all the freaking fun out of life!