This argument would be more sound, if there was more gun violence in even the US' neighbor, Canada.
Shit like this does NOT happen in Canada. Not even nearly as much, or as bad. Sure, shit happens, but there's a reason Canada is a hell of a lot more peaceful.
Just a quick example but
en.wikipedia.org/wiki/School_shooting
That list alone shows a staggering difference in violent acts. But even just in general, it's a lot more shocking to hear about gun violence in Canada. It just doesn't happen anywhere near as often.
The world needs gun control, not surplussing guns and getting them into the hands of every man, woman and child...that's just retarded.