There is a huge amount of anti-semitism in Poland - I have cousins there (by marriage) and have been there and seen and heard it for myself. Ironic that a country which suffered so much in general from the war should be so anti-semitic.

The Polish explanation, which I heard expressed when I was there, was that - in Poland - you're either 100% for the country and fellow Poles or you don't deserve to be there. The Jewish community was always treated with suspicion because they were seen as predominantly there for themselves, to the detriment of the community as a whole in a country which has always been intensely nationalistic.

I don't offer this as a true explanation, nor is it my personal view - it's what I heard expressed by Polish people in Poland. This was around 40 years ago, but I don't think there has been much change in attitude since then.