Good question. I mean, it's not like owning a gun just makes people crazy. Millions of people own them but only about fifteen thousand a year are killed by guns, through violence or accidents. So, it's not just the gun but the gun makes it very easy to hurt or kill people. So it's not just crazy or sociopathic people going off. Can't do the same harm with a knife that a gun can and don't need physical skills either.
Why do Republicans resist funding for research to answer that question?
I can see owning a gun for hunting but don't understand the "self defense" argument at all. In a way, I do own a gun -- a speargun for taking fish while diving. I'm not anti-hunting with a gun, bow or trap if people follow the regs.