Well...as much as it hurts to say this [as a gamer myself] a lot of gamers at the very least *act* like sexist, homophobic and racist asshats when online. So it's possible that they don't see it that way or have been desensitized [for lack of a better word]towards it.
Re: Bioshock 2 Racism Wank
Not all gamers, of course, but...well...A lot do.