I was a kid at a time we all had fathers that served during WWII, we had war and cowboy programs on TVs and at the movies, our parents equipped us with toy guns.
I don't think it is the video game, or the guns. I think it is the people; parents, grandparents, the kids, that no longer teach, learn, follow and enforce important aspects of a civil society.
I have absolutely no qualms about locking up a teenager, for ten years of hard labor with bread and water, for violence against others. Maybe his parents, too.