I'm not going to rule out that psychopathy can have been a good thing in some society roles, but they do look more like shirking parasites? (An evolved strategy that is turned on sometimes, depending on environment.)
[Edit: Afaik, psychopathy is not turned on after someone reaches adulthood. An evolved strategy for catastrophes would be turned on at e.g. hunger or stress.]
I especially wonder if warfare is a good example? Most of the time when humans evolved we were in a clan society. Clan warriors aren't generally known for live and let live-attitudes to people from outside their clan anyway; a psychopath would probably not stand out much in blood thirst. (And if you are in a war party, you really really need to trust the members in the party. Manipulative people would not last long when they were caught at it.)
[Edit: Afaik, psychopathy is not turned on after someone reaches adulthood. An evolved strategy for catastrophes would be turned on at e.g. hunger or stress.]
I especially wonder if warfare is a good example? Most of the time when humans evolved we were in a clan society. Clan warriors aren't generally known for live and let live-attitudes to people from outside their clan anyway; a psychopath would probably not stand out much in blood thirst. (And if you are in a war party, you really really need to trust the members in the party. Manipulative people would not last long when they were caught at it.)