People say that because they support it and they don’t think it’s a big deal. There were always anti-eugenicist movements (and always people opposed to fucking children, and having slaves, and even eating meat or going to war, and other morally shitty things justified with this excuse). That’s literally how the movements against these things came about - people throughout time have been against them. You just discount them because you align yourself with the other side, for some reason.

Tesla was not mentally well. But he had the power to make weapons, including a so called “Death Beam,” which Donald Trump’s uncle was involved with too. https://www.pbs.org/tesla/ll/ll_mispapers.html