Yeah true. Maybe we should refer to fascism and eugenics as kissing cousins. ;-)
Actually, German National Socialism's closest cousin was......German Socialism. I took the trouble to read an online article once about one of the interwar intellectuals and his affinities, and there was a group of ex-German officers who were nationalists and patriots who, where they intersected with socialism, were the seedbed of National Socialism. It is one of the things socialists today like to dissemble or simply never bring up, that there was for a while in Weimar Germany a nearly seamless continuum of opinion from the nationalist Right to the Spartakist Left, and socialism and National Socialism grew up from very similar roots. Some of the people later imprisoned or even executed by the Nazis held opinions that were in the 20's not profoundly different from those of the Nazis themselves.