I have three sons, (including a Chris), and I can't conceive the pain the Penley family must be feeling. My heart does go out to them. But Chris's history looks like a textbook case for a school shooter -- a loner, uncommunicative, angry. Threatens to blow up a bus. Father must have anger issues (history of aggravated assault). Problems in school. Suicidal.
If one of my children was in the school, if my child had the barrel of that pellet gun shoved in his back and forced into a closet, I would be livid if the authorities didn't take him seriously.
I'd bet money he is the most devatsated of all. They do tend to Monday morning quarterback themselves after an incident like this.
Before you so easily condemn, go and be in the same or a similar situation yourself. Maybe you will see what is actually involved.