The argument is that an individual has the right to bear arms, that's it. My view is that just because some morons use weapons illegally it doesn't mean another person shouldn't have the ability to defend themselves in their own home against a potentially armed intruder. America is a large place and Police aren't always a couple of minutes away, people in America can be armed and dangerous, there's way more of a hardcore drug culture involving substances like Meth that just makes people go crazy. If I lived in America I'd be definitely have a gun at home, you'd be mad not to unless you lived in a secure gated community.
So more "good" people buy guns to defend themselves from the "bad" and down the spiral they go. The drain is flowing and they can't put the plug back in, in fact they cut the plug up and let it flow away with any chance of a life without guns.