Video games, whether violent or not, are having a negative impact on the social engagement of gamers. Video games can be addicting. Children who are spending hours on end playing games are missing out on time they could be learning to socialize with their peers. All of this has a negative impact. If you add violence to the equation, it further harms the gamers ability to socialize because they begin to believe the behavior they are observing is normal. Whether it is a game or not, the gamer will become desensitized to the behavior they are witnessing.
Video games allow even the most socially awkward member of youth society to become social and makes friends. Sixty years ago similar kids would have had no friends and become loners in society. Now this avenue of friendship and development allows children of all types to find similar peers and connect.