Sadly, when truth tellers such as Jan Gross come to the fore, they're vilified as haters of all things Polish, traitors etc.
Erm, J.T.Gross is a lying troublemaker and he fits nicely along with other Jews who do indeed hate Poland and attack it at every opportunity. People such as Jan Hartman, Anne Applebaum and Michnik and his whole gazeta.
The Catholic Church always blamed the Jews for killing Christ.
Correct me if I'm wrong but I'm pretty sure the reason Christ was crucified was because of the Jews, even if they didn't do it themselves. This doesn't mean if you meet a Jewish person now, you ought to despise them, but reason the church preaches that the Jews killed Jesus, is because it happened. Anyway I go to church every single week and the subject of Jews practically never comes up.
A lot of people make up lies about how antisemitic Poland is. Sure there is some antisemitic sentiment, but generally speaking, Jews are probably much safer on the streets of Poland than any other part of the world. As for antisemitism in Poland in the past, I think a lot of it originated from land and business ownership. Jews used to own a lot of the land in Poland and many businesses. They were foreign, so many workers resented them. Eventually they were seen as the cause of all the problems and mistreatment.
It's a bit like how Black Lives Matter generally stirs up hate directed at white people, as the privileged oppressors. Many white people are not oppressors, not racist and don't have any privilege, yet they are thrown in to the same group, as the evil ones. BLM even encouraged its followers not to buy anything from any white owned companies at Christmas. It's insane, but it's from a negative stereotype formed about by nasty groups like this that some people buy in to. I think that similar things have been done with Jews and some people just see them as bad now.
Overall though I don't think there is a hatred of Jews, just a distrust, that a Polish Jew will always be more loyal to Israel and other Jews, before Poland.