Roderick Long defends Herbert Spencer:
So what common ground could there be between Spencer and the eugenicists? Both, to be sure, were “Social Darwinists,” if that means that both thought there were important sociopolitical lessons to be drawn from evolutionary biology. But Spencer and the eugenicists drew opposite lessons. For the eugenicists, the moral of evolutionary biology was that the course of human evolution must be coercively managed and controlled by a centralized, paternalistic technocracy. For Spencer, by contrast, the moral was that coercive, centralized, paternalistic approaches to social problems were counterproductive and so would tend to be eliminated by the spontaneous forces of social evolution, which would instead favor a system of fully consensual human relationships.
Admittedly, industrialist Andrew Carnegie was an admirer of Herbert Spencer, and the Carnegie Institution appears to have played an important role in the eugenics movement. But so what? I do not know how far Carnegie himself personally supported the tyrannical policies that Black discusses, but suppose he supported them up to the hilt; if Carnegie said nice things about Spencer, but also supported policies antithetical to everything Spencer stood for, this can hardly be laid at Spencer’s door.