Diction minutiae opener: while it's not a friendly or positive term to use in any context, "rape" isn't a sexist term. It's not gender-oriented. I also don't think it'd be considered more pleasant to say you repeatedly gutted the enemy team with a your KA-BAR before shooting them in the head over and over again (being what you literally did in the game) than it is to simply say you raped them. Neither of these actions would be considered socially positive if they took place in the real world; I'm not sure I see why one is looked upon less well than the other. Yeah, I'm sure some people get upset when they hear someone say, "Dude, I totally raped him hard," but I'm betting those people would be equally upset by, say, "Dude, I totally shoved my fist through his skull and tore out his spine from the neck up" (why hello there, Mortal Kombat). How is one worse than the other, exactly? Or is the recommendation that players simply not talk about their gameplay at all?
More on topic: yeah, this kind of behavior is prevalent, and not great. One of the more "wtf" terms I recall from when I was playing various fighting games in the arcade is "Jewed." As a verb. As in, "Oh man I can't believe that super combo missed - you got so jewed!" I just had to look at the guy like, Really? Did you just say that? Was reminded of this when it came up again in a Mumble conversation while playing League of Legends a few days ago (MOBA community has an unfortunately high number of similarities to the fighting game community, mostly in the negative aspects). The speaker didn't seem to understand why I was disapproving of the usage.
Honestly though, I'd say it's more of an individual thing than a community one. In those arcade fighting groups I'd play with, maybe one or two people out of about twenty were abrasively vulgar. Likewise, that one guy in Mumble is the only one of the group who uses that kind of language. Point being, Aris' argument re: "This is the fighting game community" is bullshit. It's part of the fighting game community because those people are in it at the moment; it's not some inherent aspect of the community. The community won't be "lost" if that kind of trash talk suddenly evaporates. It's not an integral element of the thing. It's just crap. Now, I will say trash talk, as a concept, is an immutable part of that community. It's part of almost every competitive community I can think of; it's just the type of talk that changes.
Changing the type of trash talk common to the fighting game community won't change the community. It'll just make it less caustic to be around.