Given that racists and slavers used the “natural physical strength” of black people to justify putting them on hard labor and some medics still think that blacks has higher resistance to pain, I wonder if when black athletes started to join mixed race sport teams, some racist would have used the same “biological advantage” argument that now transphobes use against trans athletes to claim it was “unfair” for black to compete against whites to justify segregation.
Eugenics is not, by itself, racist. It is frequently used inappropriately by people with racist motives, but isn’t necessarily so. For instance, the Ashkenazi Jews used a eugenics program to largely eliminate Tay-Sachs syndrome in their communities, by enforced genetic testing and forbidding marriage (or at least having children) for people that were both carriers of the genetic defect. There was also a strong tradition of arranged marriages, which made it much simpler.
The issue is that racists assume that a particular skin color (or ethnic group) is correlated with, for instance, being a “social parasite”, or some such nonsense. The truth is that behavior is a very complex interplay between environment and genetics, and we simply can’t make any reasonable conclusions about what specific genes will 100% definitely result in some kind of socially unacceptable behaviour, or even if that behaviour isn’t positively adaptive in some other way. We can’t even say which genes will probably result in traits that we currently consider to be negative, because genetics simply isn’t destiny (outside of cases of genetic diseases).