I have friends with hunting ranches where I could go shoot anything I want, like Axis deer, Ostriches, etc. I don't hunt. When I played UO I killed thousands of rabbits to get pelts to raise my tailoring skill. I don't see how these correlate whatsoever. I've also mowed down people in Grand Theft Auto but am very cautious around pedestrians in real life.
Humans have hunted for nearly the entirety of their existence. Mammals' forms of play simulate predation and evasion. Whether or not it's a good thing is subjective, but that humans innately find some forms of violence entertaining is pretty clear.
Regardless, given what we're seeing in real life I'm not so sure the appeal is limited to video game activity.