American's LOVED eugenics for giving them an excuse to keep believing what they already wanted to believe. Other southerners took the approach of letting their pastors tell them that "it was god's will that the negro serve us" and that keeping slaves was outright the morally upstanding thing to do with "savage races"

We also used eugenics as a "science" to make laws that allowed us to non-consensually sterilize "lesser" people.

We never actually dealt with this hateful undercurrent in our society. Large sections of america still believe in a hierarchical world order where their "type" of person is at the top and other "types" of people are less deserving. It has been holding us back and ruining our country for 250 years.