I don't consider myself an 'expert' in anything. In my study of the work of the world's leading academic historians of the Third Reich, I know that none consider them socialists, for clearly articulated reasons. The National Review, that you cited, is a partisan publication.https://twitter.com/frolickingninja/status/1030799335175475200 …
But what about the real question; are social democrats fascists? https://www.marxists.org/reference/archive/stalin/works/1924/09/20.htm …