I think you're wrong. Read Steven Pinker's The Better Angels of Our Nature, Norbert Elias on manners - even FBI statistics on violence. I would agree that no amount of social engineering (and that includes religion and morality) can do away with all violence, but history shows that it is possible to create societies in which people can choose to resolve their disagreements by not reaching for the nearest weapon. And comparing national statistics also suggests that the US has more of these incidents than other, comparable states. I for one do wish that more of these people would not kill themselves (or be killed) because I think it is in our interest to know why they do what they do.