We live in an entertainment culture soaked in graphic, often sadistic, violence. Older folks find themselves stunned by what a desensitized youth finds routine, often amusing. It's not just movies. Young men sit for hours pulling video-game triggers, mowing down human beings en masse without pain or consequence. And we profess shock when a small cadre of unstable, deeply deranged, dangerously isolated young men go out and enact the overlearned narrative.