I recall several of the other students saying the shooter was a weird kid, nobody talked to him, nobody liked him, etc. My immediate reaction was "and what did you do about it? Oh, wait, you all just kept ignoring him at best and bullying him at worst I bet."

Cruz was already acting like a psycho before he came to that school - he was constantly being transferred between schools to try to stop him doing things like threatening other students. A bunch of kids don't have the training to talk down a budding spree shooter, and it's ridiculous that you think they had an obligation to try.