Так это и есть расхождение с Геллертом, судя по Сказкам. То есть Д. был не против в отдаленной перспективе, а Геллерт считал, что отменять надо прямщас (с неизбежной кровью).

Grindelwald. You cannot imagine how his ideas caught me, Harry, inflamed me. Muggles forced into subservience. We wizards triumphant. Grindelwald and I, the glorious young leaders of the revolution. Oh, I had a few scruples. I assuaged my conscience with empty words. It would all be for the greater good, and any harm done would be repaid a hundredfold in benefits for wizards. Did I know, in my heart of hearts, what Gellert Grindelwald was? I think I did, but I closed my eyes.