No I'm not a fascist (at least I hope not...)

I'm trying to understand why we've normalised the idea of eugenics in dogs (e.g. golden retrievers are friendly and smart, chihuahas are aggressive, etc.)¹ but find the idea of racial classification in humans abhorrent.

I can sort of see it from the idea that Nurture (culture and upbringing) would have a greater effect on a human's characteristics than Nature would.

At the same time, my family tree has many twins and I've noticed that the identical ones have similar outcomes in life, whereas the fraternal ones (even the ones that look very similar) don't really (N=3).

Maybe dog culture is not a thing, and that's why people are happy to make these sweeping generalizations on dog characterics?

I'm lost a little

1: https://i.pinimg.com/originals/df/74/f7/df74f716c3a70f59aeb468152e4be927.png