He might of had mental problems, we dont know the full background on the guy. I think with me being in the UK, where we dont do things like that, I think that the U.S has alot harsh rules and laws to us brits..
So if that's how you play it in the U.S, then whatever, go for it. But we would not do that in the UK without giving the guy a chance.
If all the idiots in the world were just killed like that, there would be no need for prisons, and the population would drop, by a noticeable difference.