Because bump firing is silly. It is entertainment. I do other silly things, we all do, so I am not on a high horse here. Zero crimes - of course zero, there is no serious use (until that one schizo discovers it) By pointing at that, you would imply that the adult-style mainstream AR should be more of a problem, because mass murder has been committed using it. That's my reasoning. Draw a line, present yourself as reasonable, and you will be better listened to by the silent majority.