Man shoots church members = not a gun problem the shooter was a racist.
Man shoots school children = not a gun problem the shooter had an emotional problem.
Man shoots camera man and reporter = not a gun problem the shooter had mental problems.
Not to nit pick, but in case #1, FBI dropped the ball and allowed Dylan to get the gun when he shouldn't have. What good are background checks if the FBI can't conduct them properly? #2 Lanza stole the guns. #3 probably could've only been prevented if the tv station had filed charges against him. But they didn't. And nothing showed up on his background check to cause him to be denied a gun. Sadly not much you can do about that.
Remember the movie theater shooter down in Louisiana? That of course sparked a big huge gun debate. "We need to ban assault weapons!" "No more gun show and private sales!" "No more high capacity magazines!" "Background checks for everyone!!" Then the detail emerged. The shooter bought the gun legally from a licensed fire arm dealer after passing a bacckground check. The gun was not an assault weapon and did not have a high capacity magazine.
So I asked the people in that thread How they realistically (banning all guns is not realistic) how they would've prevented that shooting. Suddenly the anti-gun crowd went quiet and waited for the next big event so they could shout at their lungs that guns and all of their owners are the scourge of the earth and must be done away with.
Here's the reality. Are some shootings preventable? Sure. I frequently point out that Columbine, Loughner, VT were all preventable (Columbine kids had police called on them setting off explosives in a field, Loughner had made death threats against Giffords and the sheriff brushed them off, VT shooter was legally found to be a danger to himself and others.) But there's going to be shootings that just aren't realistically preventable. It sucks, but that's the real world. The videographer and reporter shooting is tragic. But it's one of those incidents that would've happened short of the anti-gun crowd rubbing a magic lamp and then telling the genie that pops out to disintegrate all guns in the US.