I understand your sentiments, jimbob, and I think you're right about the fact that it's important to attach responsibility to the individual who selected this as his course of action. However, I disagree with you that it would be a deterrent to treat these acts as truly shameful. If you're deranged enough to deliberate about and eventually decide on going to a mall with a rifle to shoot people, do you think you'd stop and think to yourself "Hmm, this isn't going to be though of as a noble act. Maybe I won't do it after all"? I sure don't. The way to stop things like this is to allow people the means to defend themselves.
Just as this pathetic individual should be held solely responsible for his acts, so too should everyone be responsible for their own protection and the protection of their families. If someone is determined to do something like this, whether it is for attention, because their cheating spouse pushed them over the edge, because they received a vision, or really for any reason, they will do it. This, unfortunately is a fact. However, the severity of these types of things might be reduced if people are armed and ready to fight for their lives against such senselessness. Instead of nine dead, it might be half that, or a third that. Who's to say? This, to me, says that the real issue here is that of people being able to protect themselves if something like this does happen, not somehow keeping these incorrigible lunatics from doing them in the first place.