This episode is why I like and appreciate the Law and Order. It doesn't show black and white, it gives an insight into most of the aspects that build up the story. It is unarguable the kid deserves punishment yet who can say what is really in his head, how he felt in his sixteen years when bullied at school and no one to help him. I'm far from excusing him however I agree here with Jamie Ross that something should be done to stop this ghastly shooting spree now coming already to Europe. And I don't think the security measures at the entrance of each and every school are just the whole of the appropriate answer.
This episode shows what an impact the crime had - we watch the family of the shooter but at one moment the prosecutors stand in front of the families of victims and these rightfully expect the State is going to protect them and especially their children, that everything will be done to prevent this from reoccurring. And the father of the shooter is well aware of that, his testimony in the D.A.'s office and then at the trial belongs to one of the most moving moments of the series.
Together with the Teenage wasteland episode we have been shown in this season this society is somewhat sick and the justice system can severely punish the perpetrators but it can't heal it.