I disagree. There have been numerous studies in the literature with primates about fairness and other prosocial behaviour - it's pretty standard in species with cooperative breeding and that's what fosters the familial or primate tribe mentality. Fairness within a group, but rarely without. Given the divergent evolution of us and other primates, I would suggest pro-social fairness is far older than many of us think. Human children are particularly adept at ensuring fairness is played out - and in-group/out-group dynamics begin at a fairly young age. I'd say around 4 years old. There's something going on there.

Psychopathy likely has a genetic and an epigenetic basis meaning they will always occur, whether or not they flourish in the army or turn into serial killers depends on their childhood experience as well as the construction of society itself. Psychopaths are particularly well suited to capitalist economies, but they are also well suited to Communist economies too. I don't believe psychopathy is a self-deceptive quality - and I don't think the scientific research will bear out that interpretation. Genuine psychopathy cannot be healed, it can only be mitigated by good experience.

Psychopathy and out-group thinking are different and there can be a form of collectivist thinking in which empathy is reduced - that's very much what happens with White Supremacists, but it's also what happens with every in-group/out-group. The one sided conflict between the Hutus and the Tutsis back in 1994 did not have a 'whiteness' component, but it did have a collectivist othering component. There was a failure of collective empathy but this isn't indicative of psychopathy.