The Polish holocaust debate is rather interesting, because Polish people (as in, ethnic Poles) were both victims and perpetrators; millions of Polish were killed during the holocaust, and the plan was to kill up to ~85% of them and use the rest in forced labour (i.e. slavery, basically) to make lebensraum for more worthy people. Slavs weren't considered as bad as Jews, but still untermenschen.
At the time same, it's obviously true that some Polish people were also perpetrators.
It's interesting to watch the debate; it's not just far-right extremism or fascism that opposes the more nuanced view. There are a lot of emotions involved and it raises interesting questions about what it means to "be Polish", to "be a victim", group identity, shared national identity, etc.