First shift the historical responsibility to some rather abstract "Nazis" and ignore the fact that most of the Jews were Polish citizens, then start encouraging usage of misleading terms (https://en.wikipedia.org/wiki/%22Polish_death_camp%22_contro...). Give it one century and people will think the victims were aggressors, and vice versa.
For whole world "Polish death camp" sounds like it's Polish responsibility. "Nazi crimes" etc. sounds like it's some abstract Nazis, not democratically elected German government with huge public support. Ignorant public all around the world can think "Who were these Nazis? Maybe they were Polish?" Then things like Jedwabne: http://www.ppu.org.uk/genocide/case4.html gets blew up out of proportions ignoring that there is a plenty of doubt on what actually happen. Rather mediocre movie Ida: https://en.wikipedia.org/wiki/Ida_%28film%29 gets Oscar award, (speculation) because it's main story is about Jedwabne and portraits Polish citizens as Jew-murderers. I see it as slow and continuous process of shifting blame using PR methods, for political and material gain.
All of this in the background of a big controversies and political struggle about Jewish organization claims for retribution money and property.
It's sad that a nation directly most affected by WWII, than struggling with Soviet occupation that was a WWII consequence, now is under PR fire to manipulate world public into blame it for the horror of it.
> encouraging people of other countries (like the US) to think "that was a German action, it could never happen here."
"That was <<Nazi>> action, it could never happen here.