I can't ask him what he meant as he died almost 20 years ago, but I believe he was speaking emotionally as a reaction to being attacked as a kid as well as some neighbours helping the nazis by turning over some people from his family that were trying to hide. Of course the Nazis are to blame for the industrialised systematic murder they introduced to Europe (not only again Jews) and I never claimed Poland as a nation was as bad as the Third Reich was (and either way I don't condemn people for the sins of their ancestors, especially those that were done before they were even born).
There are some facts of note here, not only emotions. You saw the thing primarily through your grandfather's lens, or kinda reconciling it with the "other side" online (my guesswork), but I offer starkly different perspective.
1. There were times and nations where "anti-semitism, period" was a complete political program that won legal democratic elections.
2. In Poland this program was always in substantial minority, geography and economics nonwithstanding.
3. People susceptible to such programs are a part of the problem, not a part of the solution. The program is about labels, but it breeds the hate towards an actual neighbor. Even if the idea is changed to "it's all because of Zambians". Or Poles.
