Okay, I'll argue the other side, then. His abnormal ideation caused by a chemical brain dysfunction made him incapable of judging right from wrong. A wild surge of serotonin caused him to stalk, kidnap, and r*pe a woman, beat and rob a therapist, and make murderous threats against an accomplished magazine editor. The best society can do is drug and incarcerate him in a softer, padded cell than your average criminal would rate. Labelling him insane distances his actions as being something that's somehow mysteriously inhuman yet still pitiable and treatable, so that we can avoid the sticky problem of Justice altogether. And everybody can still be scared of the inexplicable bogeyman that might get them, too, if they're not especially nice to all the Little People in the world. Because, you know, they just can't help themselves, the wretches, and we owe it to them to see their names in the papers if they do their monster dance convincingly enough. Disgusting.