I definitely agree with your comments and have thought the same myself. If they don't have Jews, Christians, Westerners, etc. to hate/kill, then they do it to themselves. They don't like animals. They don't like people. They don't like anything that's alive. This is a generalizaiton, but I think it holds true for a good portion of them. We have to face it. We can't wish it away.
You are also right that if they don’t have an external enemy then the Sunnis will kill Shias and if not that they will kill sub tribes. These people are inherently incompatible with the modern world, have loyalty only to their tribes and no rational thought or dialogue will ever change that. The liberal apologist who believes that if you just get along with them and appease them, they will leave you alone is a suicidal lemming.