Most videogames, whether or not they choose to profess it, are rooted in violence. And we’re not just talking about bête noires such as Manhunt, Call Of Duty or Carmageddon. Something as innocuous as Super Mario Bros. involves jumping on enemies’ heads to make them disappear, and at the end of each final stage the big boss plummets into a fiery pit. Space Invaders is all about the shooting. Street Fighter requires beating your opponent into submission. Even Tetris involves making harmless blocks disappear. Call it “deleting” or “subtracting” if these euphemisms make the killing and destroying more palatable. There is no doubt that to progress in any videogame you must be…