By the bsame argument, prison works,
because criminals are kept locked up unable to commit crimes, except against each other.
That is why there is no crime, and, therefore, no need to be concerned about violent video games anyway.
Back in reality, however, these representatives of our species who spend all their time playing crime sims, war sims, and beat-em-ups, how well-socialised will they be? When they do occasionally interact with other homo sapiens, will they be civil and tolerant, or will they fail to connect on a human level, and, instead, treat the other party like they treated their X-Box the last time they got Red Ring of Death, and put them through the nearest wall?
There are sometimes slightly unbelievable stories told of the effect of some games on individual minors, such as,
And there was a war fling game for the dear old Sinclair ZX Spectrum where, with the greatest skill, you still couldn't get the bad guys without inadvertently strafing some of the refugees on the ground. Human shields for the legitimate targets, so not my fault. War is hell.
And a magazine giveaway game that for some reason was isometric-perspective squash played with baseball bats over a tennis net. But if you advanced to the net, the computer opponent came over to meet you, and you could beat him to death with your bat. First player to ten points wins.