That can wait for another thread, IMO. You will not change that person's mind, he is a very distinct minority on FR, and all it does is detract from the larger tragedy.
One individual on the scene with the proper mindset, armed or not, reacting in proper fashion the second the incident begins, often stops such atrocities in short order.
Not in this case. The perp was a local. He was not in a position where he would be suspected of wrongdoing until it went down. He could have easily taken out one unsupecting armed man.
Let's let this one go from a 2nd A viewpoint. He could have just as easily driven his milk truck through the school and killed even more people, not gun requied, no way to stop him.
"He could have just as easily driven his milk truck through the school and killed even more people"
Sssshh! Don't give the crazies any more ideas! $;-)