What always comes up first, here in europe, is always:"Oh those americans and their weapons ...bla bla". Your relationship to weapons is a little weird to me as well, but i think you're used to it, you know what you do and that most people are sensible with that.
BUT on the other side, it's so difficult to get weapons over here and those tragedies happen here, too.
Maybe you heard of it: Last year, one a..hole bombed government buildings in Oslo,Norway and then shooted 69 people, most of them teenagers, for racist reasons. He said he was on a "crusade" and wanted to "clean europe" or some crap.What happend?
Almost nobody was talking or careing about the victims and their families. Instead of this the guy was given weeks of spotlight. Every channel, every newsshow showed everything about him and his life. He made a triumphmarch out of every trial. And you saw that he really enjoyed it.What a disgusting situation.
So i think, the influence of the media, especially TV, is a major point. All what matters are the numbers of sale and exciting stories and faces, every day. A Star is a Star, no matter if it's a singer or a mass murderer. I don't know if you have this idiom in the US too, but in my opinion, they put oil into the fire.And they're totaly aware of it.