Exactly. I had a psych professor who actually worked in a mental hospital tell us the story about the catatonic patients. These patients were on the floor, in the fetal position, with their thumb in their mouth. My prof would go over to them and give them a sharp kick to check their reaction. They would kick him back! My prof explained that, no matter how mentally impaired a human being is, they never lose their sense of right and wrong. They will continue to have a moral code. The mental illness defense is something made up by trial lawyers to make a buck.
Yes indeed. I had one idiot one time, who had a habit of exposing himself to female staff members. He tried to tell the psych doctors, that his lawyer said it was a disease, so it was excusable. They weren't buying it. As messed up as he was, he knew what he was doing. They just told him the lawyers always say stupid things, to try to drum up business for themselves.