So I have been watching the popular new Netflix series (Dahmer), and in one episode, they try to get him off with the insanity plea so he would go to a mental hospital rather than prison. However, he was found to be sane and guilty at the end of the trial. As someone who majored in psychology and still studies it to this day, I had to question how a serial killer could be considered sane. Morality aside, generally, serial killers kill strangers, they aren't getting vengeance, monetary or social gain, and they are risking their freedom and their life if there is a death penalty in their state. Many serial killers had dark pasts and childhood trauma; I am by no means excusing or justifying their behaviors as many of us had rough childhoods and did not go on to kill people, but I do believe you have to be pretty mentally ill to be a serial killer and trauma effects some people much worse than others.
Edit: I am aware that many serial killers have severe Anti-Social Personality disorder and Psychopathy, but why shouldn't these be considered forms of insanity?
What are your thoughts?