Except a) sounds like it might be true, and b) the outcome of "not guilty by reason of insanity" should be, well... many years of being removed from society in

Except a) sounds like it might be true, and b) the outcome of "not guilty by reason of insanity" should be, well... many years of being removed from society in order to prevent further damage and possibly an attempt at treatment/rehabilitation. Which is basically what criminal sentences should be like; at least in situations like this that involve irrational harm of others with no personal gain, which you cannot correct by disincentivizing them with punishment.