If you go to a library and look at encyclopedias from the late 1920’s and early 1930’s you might not be so sure. Under the topic “Eugenics” there are sometimes references to Darwinists (not Darwin himself) that are in support of helping evolution by removing undesirables and preventing their births. It might not have been directly connected to the nazis. It might have just been a general world view at the time.
Leonard Darwin was president of the Eugenics Society. Poulton was vice-president. Punnet was a member. So was Julian Huxley and J.B.S. Haldane. R.A. Fisher and Karl Pearson were eugenists. Darwin's cousin invented the word "eugenics". Have a look at my FR page.