I would have to say that it depends a lot on the child's school and home environment, and how violence is tolerated outside of the video game. games can be a great way for kids to vent frustration rather than physically turning it on another human.
My siblings played extremely violent video games growing up. As adults, they are animal and people lovers that fight everyday for humanity and tolerance. As far as I know, they are still catching houseflies and letting them go outside rather than swatting them. I didn't play those games. And I own a flyswatter.