I remember a conversation in the coffee room when I was in graduate school. An American graduate student with a German surname was trying to get an Israeli graduate student to say that the Poles shared in the blame for the Holocaust, and the Israeli refused to take the bait.
There were plenty of people in other countries who participated in the mass killings, but Poland would be at the bottom of any list I’d draw up (and I have no horse in this race whatsoever). In areas in which the Nazis initially pushed back the Soviets (and which later were re-incorporated into the USSR), the populations there were more brutal than anything I’ve heard committed by Poles.
Funny how the Austrians, get a pass, though.