There's no such thing as "good genes" and "bad genes". There's just genes, and whether they're good or bad depends on an ever-changing environment. The only real measure of a population's genetic health -- how likely it is to survive far into the future -- is its genetic diversity. With their insistence on "racial purity", racists put themselves into the "loser" category by reducing the genetic diversity of their population. Sorry, farther into the "loser" category.