This may be 'out there' for some, but I've wondered if an aspect of this is to have a ready supply of people some of whom over time will shoot up a school or fast food joint. It helps continue to push other agendas that the same type of people go for. I don't think it's an originating reason for it. It's cause would be more along the lines of when you no longer believe in a God, you automatically tend to put yourself in that position.