You sound like you are either a counselor or been there done that.
I read Dr Robert Hare’s “Without Conscience” and learned a great deal about psychopaths. And with the understanding I got from that read, yes I can see where a psychopath would not be bothered.
Brutal war would be a paradise for Ted Bundy types. We are watching a Netflix documentary on this guy right now. Just brutally beating to death random young girls is really hard to grasp.
I’ve participated in a couple of groups to get my mind right.
“... the vet’s brain is forever rewired, something that just cannot be helped. Self medication only worsens it whether it be all or a combination of withdrawal, isolation, alcohol or drugs.”
As an old shipmate says; “no one knows what’s going on in your head”.
Two excellent book on combat trauma are “Achilles in Vietnam” and “Odysseus in America” by Jonathan Shay. Well worth the read if not kept handy for re-reads. Dr. Shea was perhaps the first to advocate treating combat trauma as an injury and not an illness or disorder. In treating combat trauma, Dr. Shea also pioneered the concept of “moral injury” which may be loosely defined as; a betrayal of what is morally correct by someone holding legitimate authority in a critical situation.