I don't think there is anyone singular fan base that is horrid just listen to any console war disscussion for that, for the majority of games they're on both systems or the pc purists vs the console 'softcores' it makes your love of people vanish.
It is always segments of a community, however each game has a responceability to police it and thus I have to say (this maybe because I haven't played Battlefield) mondern warfare.
My brother got black ops and I am not good at shooters but am very competive so I kept playing so I could get good, now I expected the various noob bashing comments to hit hard but apperent I am not that bad or they weren't that down on the newbie.
What made me sick to my soul is the various disgustingly racist comments I heard on there, I am not exactly polticially correct, I say black and white and I get my asians mixed up so understand that this was beyond anything I heard and I lived in outback, outback with some people with some vicious drinking poblems.
Just stuff that jokes, oh and the homophobic anti-gay comments were beyond belife as well.
Now it's not just that but the number of profile pictures that are dicks, ass or viginas or something vulgar was stupid.
The reason it goes to them is because of there policing of this problem. Not once a have I ever heard of a banning or any responce appropate to these peoples actions. You know why skinheads are skinheads and not metal fans? because metal fans said no we like screamo music not rampant racism.