Worth noting that Harry Laughlin was not an outlier. Many of the 'great and the good' at that time were supporters of eugenics and included Winston Churchill, GB Shaw, Neville Chamberlain, JM Keynes, Jack London and HL Mencken. Denmark, Sweden, Norway, and Finland all brought in eugenics laws in the 1930s. Those deemed to be unfit to reproduce were sterilized.
https://www.economist.com/europe/1997/08/28/here-of-all-plac...
Oh it wasn't in isolation - a lot of well known names in many nations had an interest, and there was varying degree of popular interest too. It seemed particularly popular in the Nordic nations, and America. The were eugenics societies in most of the major nations. America had popular societies in many states, it was in the media, and the US were among the earliest to bring in eugenic laws - and the last to keep them around.
So in the context of OP's comment it seems very unlikely that many were completely unaware of what Germany was doing along similar lines, and going so much further. Whether that was still viewed as OK in the context of the time - a time before the holocaust - is of course far harder to judge.
