As far as I'm concerned, there is only one way in which a computer game can ever be directly responsible for a person's death, and that's when the disk spontaniously leaps from the shelf and decapitates an innocent bystander. Everything else is people killing people.
Speaking as an avid gamer (and student developer) I will say this: Games are violent, and are also stimulating, and enjoyable. I actively enjoy taking a shotgun to the Combine troops in Half-Life 2, or shooting it out with the Ballas in GTA:SA. Such violence is FUN, and, as a species, we get a kick out of death and injury. People refer to the "dehumanising" effect of violence, when the fact is that we are at our most human when we are killing something.
I tend to believe that using the word "dehumanisation" in relation to violence is a fallacy. we've been killing each other for millennia without computer games around. Games are just another aspect of the internal hedonistic psychopath inherent within all human beings - we play games because, as a species, we gain a certain degree of pleasure from violence. This is hardly unexpected - we're predators who evolved over vast reaches of time to hunt and kill prey, and take satisfaction from both the hunt and the kill. Because directly pandering to that subconscious predatory reflex (by, say, hunting caribou with a spear) is no longer really considered acceptable, anything that stimulates those primitive pleasure centres of our brain that are directly linked to the testosterone and adrenaline glands is fair game as entertainment - James Bond shoots the goons and kills the bad guy partly because The Good Guy Always Wins, but also because our whole species is wired up on the genetic level to be mesmerised and excited by the prospect of violence.
Why do people stare at car crashes? Why do we watch boxing matches? Why do we watch football games, rugby games, hockey, etc.? Because, when all's said and done, we're all hooked on the knowledge that somebody's getting hurt. We none of us feel actively sickened when we see Kurt Angle take a chair to somebody. Why?
Deep down, all of us feel the need to hurt something, or to be there when something gets hit. It's darwinism in action - we like violence because we're not the ones getting hurt. Survival of the fittest. Pandering to the violent urge is no bad thing. The trick - one that any normal human being learns within a few months of being born - is to learn where the line is drawn, where the pacifying substitute for the primal life-or-death struggle HAS to end, and the business of actually being an intelligent species starts.
The people who shoot up their schools, or take a samurai sword into a department store and start slicing people up at random HAVE SOMETHING WRONG WITH THEM. This malfunction is not a predilection towards violence- everybody has that. the malfunction is an inability to recognize where the violence must end.
Computer games in no way shift that moral barrier - anybody who can distinguish even the most basic levels of "right" and "wrong" knows that killing somebody for kicks is neither normal nor right. No amount of game time, even of the most gory and ultra-violent games, will ever convince a normal human being to open up with a 9mm on the street. Of COURSE they stimulate violence - that's why they exist. But no game will ever be able to persuade a normal, healthy, sane person to go kill somebody for fun.
