This has nothing to do with lofty constitutional issues.
Any shooting is an isolated incident. But the overall cause of the problem is self-evident:
Supply and Demand.
1) There is a huge industry of gun and ammo manufacturers, not to mention a firearms press, marketing industry, political arm and other infrastructure, getting very rich pushing weapons of no legitimate civilian purpose that eventually arm criminals--and occasionaly, the insane and sociopathic.
2) You have a huge number of trailer trash rednecks who are just dying to have a legitimate excuse to shoot themselves a nigger.
Everything else is bullshit.
It doesn't take a cultural anthropologist, criminal psychologist or a constitutional scholar to figure this out. It's as plain as day once you get your head out of your patriotic ass.