Two things

• If you look at how the accusation of antisemitism is invariably used to excuse the actions of Israel, it's far too often a case of non-Jews telling actual Jews what Jewishness is supposed to be like, sometimes even de facto calling said Jews antisemite (or, other words, "Bad Jews"). If as non-member of a community one is telling members of that community what their community's values are supposed to be, then it's probably time for that person to stop and do a little instrospection and hard thinking about their own posture.
• Being a Jew or part-Jew is not the same as knowing what the Holocaust and Nazism was in all their dimensions and implications and it certainly doesn't make one a Genocide specialist. Hearing the stories, especially from somebody with an early XX century set of morals or second or third hand is not the same as understanding it in depth, especially with XXI century values - otherwise there would be no needs of History as a Science discipline - even if it feels almost like you were part of it: do not confuse stories of the stories about what happenned with fully understanding what happenned - even people who were in or saw mere accidents or crimes rarelly fully know what happenned: just go read about how humans are far from perfect witnesses, much less 2 or more levels removed from actual witnesses in such a grandiose (not in a good way) event. That's not an etnicity thing, it's just human. That said, I can understand how it would feel insulting for somebody whose family was directly hurt by it to hear people whose family were not, casually use those things as references or even preach their moral take on them - kind of like watching somebody piss on one's ancestors' graves. That said, for Jews whose family was not affected by those things to do Holocaust-interpretation or Moralizing should also feel equally or almost equally disgusting for those whose family suffered from it - it's still those who did not suffer preaching to those who did.

Anyway, my original point is that his was a Humanist behaviour, something that transcends etnicity, even if added to that was also the feeling that people were pissing on the graves of his ancestors due to his actual ancestry. I don't think it's necessarily the product of superior knowledge, more of being the kind of person we all should aim to be and a superior awareness of such evilness due to how his own family was affected by something similar.