The ratings thing is largely ignored anyway. Its there, but it isn't strictly enforced and most parents either don't pay attention or don't care what their kids are playing. But that's fine, because a video game isn't going to make someone evil. Bad kids will do bad things, but that has nothing to do with the games they play.
After Columbine happened over 10 years ago the media and the government and everyone blamed Marilyn Manson and video games. How many people took the time to think that maybe the kids being bullied at school might have had something to do with driving them over the edge? But that would actually require the schools and parents to get off their asses and actually do something about school bullying, and they can't have that so they went and blamed Manson's music and games like Doom instead, because that way they could pat themselves on the back and feel like their little moral crusade did something, but it didn't. Kids are still being bullied in school and being driven to suicide and/or murder even though the censorship is in effect, and even when neither music or games were involved at all.
True, many of those same kids did play violent games and/or listen to Manson's music... but maybe that's because Manson was the only one who understood how they felt so instead of that being the cause of their problem it was actually something they found solace in (if that makes sense).
I don't remember how old I was when Mortal Kombat came out, 10-12 or something like that I guess... but I played the game and I never went berzerk and killed anyone as a result of playing that game. But I can see how someone who had to live with constant and severe bullying might be driven to going berzerk, so that's what I think society needs to do more to address instead of blaming entertainment media.
Hell, if anything games like that would allow bullying victims a way to vent out their frustrations in a way that harms no one. Maybe it does more harm than good to censor stuff like that.