Well, didn't the Nazis themselves prevent people from voicing concerns for the Jews? I guess I don't see how that's not the same thing, except that it was the bad guys who did it?
My point is that they used the same tactics (obviously different times/technology/etc) themselves to prevent people from supporting the Jews. So "the same practices being used against someone who is not them" is something that has already happened.
NOTE: My knowledge of history is not great. Let me know if I am incorrect.