I find it depressing that a discussion is going on about whether you should have to care or not. Is this really the mentality people have nowadays? Agreed, stuff like this happens on a daily basis (though not as extreme as this) and people often forget about it, but there's no reason to be rude about it and say you don't care. If you have to say that, don't post at all.
My respects go to the families and everyone remotely connected to it. It's horrific to think about it, though I do have to agree with previous statements about how the US government should adjust the weapon-law... Although I guess it's not that easy to do.