He's got this idea that if society is saying "all war is good, all glory to the victors" then people will respond with a discourse that says the opposite, like "all war is bad, woe to the victors" and only after move to "there are some just wars"
I think he brings it up talking about the Mo-ists in Toward an Anthropological Theory of Value and brings it up again (maybe not by name) talking about west coast people and whether they forage fish or acorns in Dawn of Everything
I was gunna' guess projective negation.