Race is indeed an ambiguous term in general, as there are overlaps. But I have to wonder whether it's the stigma associated to the word especially post WW2 and

Race is indeed an ambiguous term in general, as there are overlaps. But I have to wonder whether it's the stigma associated to the word especially post WW2 and Nazi eugenics that made some anthropologists reconsider and say "most differences are cultural". There are obvious aesthetic (not functional) differences between populations. These are enough to distinguish between races within other species so I'm having a hard time finding an authoritative explanation for why it would be different for humans. I find no challenge in treating people as equals without the need to think they are the same race so such an argument based on sociology is not as convincing as a biological one.