Reciprocity just makes it preferable to cooperate rather than engage in predation.

t’s not that Reciprocity is good for all of us – even though it is. It’s just that it’s the only condition under which it’s not more profitable, preferable, logical to kill you, take you things, and enslave your women and children.

Personally, I kind of prefer the whole kill, take, and enslave thing, but for the good of the women among my kin, I realize they will be happier in a complex, prosperous, cooperative society.