The great irony of eugenics is that the only real measure of the long-term health of a population is its genetic diversity, which leads to the exact opposite conclusion of eugenics. If you want your “race” to survive and thrive, you should interbreed with other races, not try to cull and “purify” your own. There’s no such thing as good or bad genes, because that depends on the environment which is constantly changing. Eugenics is just wrong in every possible sense of that word.