First of all I want to make it clear that I'm not defending Noah's use of that slide - I think it was dumb. I don't think that you think I approve of it, but I just wanted to get that out of the way up front. For the sake of argument though I'll be operating under the assumption that denigrating an ex- in a slide is a good idea, and the issue is to choose the correct word.

Back on topic, the ideology I was thinking of is the idea that men and women aren't statistically different (or if they are, that mentioning such things is impolite). I would argue that "bitch" captures a characteristically female way of hurting a man with whom she's had a relationship. (See Carmen for the high-culture version, or Louis CK for the pop-culture version - http://www.youtube.com/watch?v=ZpW3orlfp7E) It's true that the word also carries other connotations, but I don't think that was the intent.

I agree that it may be "lazy", but from a purely practical perspective, it would be tough to find a similarly short word (short enough to fit on the bobble-head) that conveys the meaning. "Evil" might work and is gender-neutral, but the class of actions that make one "evil" are broader than the class that make one a "bitch".