Ugh. Agreed. One thing we haven't talked about is pure rage. Not everyone who beats someone to death is a psychopath. They may have various diagnoses or none at all. Just the type that gets easily enraged, injustice collectors, wife beaters, child abuser types, vengeful, feel the world owes them, etc.
We see cases every day of horrendous people who systematically torture their kids or step-kids to death or beat their wife to death. Most/many I would think are not psychopaths. They may have been raised with violence or were
never taught how to regulate their emotions because they were super spoiled and indulged. Given whatever they wanted. Everything they did justified by their parents or excused or denied. So when they are told no or not given attention they explode with rage. Or they just feel a ton of anger all the time and enjoy venting it.
One doesnt have to be a psychopath to be like that.