Things might have been said and exchanged that just set someone off. It's probably doubtful that this man was actually out 'hunting' for kids to kill for the slightest of reasons, or the like. But it's also very possible that this person should have avoided confrontation in general because of an acute ineptitude at coping with it peacefully...with an easily accessible gun sadly providing an 'instrument' of expression in an extremely agitated state. And yes, I do agree that guns can at times seemingly empower people beyond wiser judgment. Unfortunately, you often can't predict that nor, as mentioned, may not have preceding evidence for predicting it.