Granted, belief in God is common denominator in all the things you described but it was the false doctrine of the organized religions which brought them about. The simple fact of someone believing in God does not make someone go out and kill others unless their belief is distorted by teaching them that it is God's wish for them to do it. There could be one deranged person who believes God is personally telling him to do something like that but the same could be said for a deranged atheist who decides to kill Christians. Allah does not tell Al Qaeda to go out and kill in his name it is the Imans of that radical Islamic faction that tells them it is God's will. God is in all of us everyday and it is our free will which determines how we use it.