So do you think killing innocent civilians, looking at a soccer mom who's begging your for her life then casually blowing her brains out (and getting a cinematic closeup while you do so), is the same as killing terrorists? Because that's what you're saying when you generalize to "violent games."
In GTA, you can kill anyone, including soccer moms who, may or may not be terrorists. Why do you not hold that game to the same standard? Is it really something as arbitrary as a close-up kill cam that makes you want to create a double standard?
I've only played a bit of GTA IV, so I couldn't say. I wouldn't say that it's "totally cool" shoot people in other games, but they certainly make it seem more fun than Hatred does, I'd have to play Hatred to say for sure. But think about it, if that Nathan Explosion guy with the fake batman voice had been shooting people with toasters out of Fallout 3's Rock It Launcher, the trailer wouldn't have been disturbing, it would have been funny. I don't care if Hatred is ethical or not, I just don't think it looks fun.
That's why I say it's the context and motivations that people have a problem with. If it were silly, nobody would care. It's because the character says he's going to kill people just to satisfy himself that people have a problem with. Even when you play as the bad guy in a game, the game often portrays your evil actions in a positive light and promotes the idea of the ends justify the means. In this case, it's just personal satisfaction of going on a killing spree. People who can't or simply don't want to separate reality from fiction would naturally have a hard time dealing with this sort of thing.
I, however, have no trouble separating the two. It's often difficult for me to become immersed in video games as a result. I view digital characters as digital characters. I may relate to them or even sometimes feel something for them, but I can always see the man behind the curtain, so to speak.