The problem with comparing the US to any other country, is that there are no countries that compare. Sure, violence is inevitable and happens everywhere, but violence in the U.S. takes quite a different form than elsewhere. Nowhere else do we see people frequently slaughter innocents and peers in suicide rampages quite the same way as we do in the U.S.

The U.S. is the only place in the world where this frequently happens, but it is not the only place in the world with poor mental health treatment, so you really can't just blame it on nutters and the health system. It is the only place with poor mental health treatment, a vindictive culture and a shit ton of easily accessible guns, though. Clearly this is a multi-faceted and complex issue that can't just be argued away as "no no, it's clearly this ONE thing that's at fault".