Pointing out who is right and who is wrong does absolutely nothing to fix the problem, which is that every few years we seem to end up with a dozen or two dead kids somewhere, usually including the shooter. Pointing out that the shooter was a bad person isn't going to make those kids live again, and it won't stop the next person from doing the same thing.
In many of these situations some kid feels like they're all alone and they lash out against everybody. Sure, the other kids who wouldn't be caught dead talking to him didn't deserve to die from it, but that won't help them if the bullets start flying.
Our criminal justice system seems to be built around deterrence - if you treat people who commit crimes harshly then nobody will want to commit a crime. Clearly that isn't going to work in cases of murder-suicide, but we're so attached to our system that we will do ANYTHING else to try to fix the problem before we even think about helping would-be criminals before they become criminals. Heck, last night they interviewed a homeless guy on the radio who was having trouble getting into a shelter before a cold front moved through, and he said that it wasn't a big problem if he didn't get in - he'd just do something to get thrown in jail for the night. Apparently we don't have money for $3/night beds in a shelter but we have plenty of money for kevlar, police cars, and holding cells. I'm sure somebody will come up with the bright idea of putting the holding cells outside in the cold to deter this sort of behavior.