It is better for all the world, if instead of waiting to execute degenerate offspring for crime, society can prevent those who are manifestly unfit from continuing their kind. Three generations of imbeciles are enough-Justice Oliver Wendell Homes, in Buck v. Bell, 1927.
Posit a world where the Weimar Republic muddles thorugh the Depression, and the old world doesn't crash and burn. What ends up happening to thei dea of eugenics? Even in OTL, sterilization of the mentally handicapped continued into the... 1970s? in Scandinavia, and there are reports of American doctors steilizng Native Americans until around the same time.
Could we end up with it never going out of style?