CNN to the contrary, religion doesn't kill people. People kill people:
Why single out a belief in God as a cause of violence? What about the "religion of the state" or the "cult of personality" as practiced under Hitler, Stalin, Mussolini, Mao, and Saddam Hussein, among many others of their ilk?In fact, religion fosters cooperative behavior and generosity toward strangers, which is probably why Red-Staters are more generous givers than Blue-Staters. Religious belief, true or not, seems to be a beneficial evolutionary adaptation that, on the whole, causes believers to live more positive and productive lives than non-believers.
Violence comes from humans. God -- or, more precisely, religion -- is but one excuse for violence. There are many other excuses....
The influence of religion on human behavior is asymmetrical because the anti-social aspects of human nature -- dominance, enviousness, and aggressiveness -- outweigh the pro-social ones. That is to say, religion is a counterweight to our natural anti-social impulses, which would (and do) dominate our pro-social ones in the absence of religion.
UPDATE: Thanks to John Ray's Political Correctness Watch I found this article about the study which finds that religion fosters cooperative behavior and generosity toward strangers.