I seem to remember a quote from a US Supreme Court case that was at the height of the eugenics movement in America.
The quote was along the lines of "three generations of imbeciles are enough", giving reference to a particular case of sterilization for someone who was the apparent third generation imbecile.
If I recall correctly, the justice in question was Oliver Wendell Holmes.
At any rate, eugenics seems to have been in style worldwide during those decades. I would actually doubt that a single culpable group can be fingered for the popularity of eugenics during the early 20th Century. I also wonder whether it simply became unpopular, or was repudiated by the likes of Chesterton.
(Occasionally, I have seen people try to draw a straight line from "the preservation of favored races in the struggle for survival" in the subtitle of Darwin's Origin of Species to the "favored race" ideology of the Nazis. That seems less tenuous than Hale's claims; it also appears to be made out of the same raw material.)