Earlier quoted context omitted.
Humans are both. Empathic and cooperative with their tribe, vicious and xenophobic towards other tribes. It's a perfectly cromulent survival strategy. Organized groups larger than some 200 members are a very modern thing.
Hahaha "perfectly cromulent" - I see you! (fellow fan of the Simpsons!).
> fellow fan of the Simpsons
Not exactly an unknown show.