The Polish Government-in-Exile, during WW2, frequently, actively persecuted Jews...

From a statement by Yad Vashem, 5 July 2018:

The announcement on 27 June 2018, regarding the intention of the Government of Poland to revise the controversial amendment to the Act on the Institute of National Remembrance, approved on 26 January 2018 by the Polish Sejm, stirred hopes of a positive development and a step in the right direction.

Pursuant to the announcement, the Prime Ministers of Poland and Israel released a joint statement declaring the deletion of Sections 55a and 55b of the amendment, which defined any public reference —“contrary to the facts”— that the Polish Nation or the Polish State was responsible and/or shared responsibility for “Nazi crimes committed by the German Third Reich” as a criminal offense, subject to up to three years in prison.

A thorough review by Yad Vashem historians shows that the historical assertions, presented as unchallenged facts, in the joint statement [by the Prime Ministers] contain grave errors and deceptions, and that the essence of the statute remains unchanged even after the repeal of the aforementioned sections, including the possibility of real harm to researchers, unimpeded research, and the historical memory of the Holocaust.

The statement contains highly problematic wording that contradicts existing and accepted historical knowledge in this field.

The joint statement’s wording effectively supports a narrative that research has long since disproved, namely, that the Polish Government-in-Exile and its underground arms strove indefatigably—in occupied Poland and elsewhere—to thwart the extermination of Polish Jewry. As such, they created a “mechanism of systematic help and support to Jewish people” and even took vigorous action against Poles who betrayed Jews. Although the joint statement acknowledges that there were cases in which Poles committed cruelties against Jews, it also says that “numerous Poles” risked their lives to rescue Jews.

The existing documentation and decades of historical research yield a totally different picture: the Polish Government-in-Exile, based in London, as well as the Delegatura (the representative organ of this Government in occupied Poland) did not act resolutely on behalf of Poland’s Jewish citizens at any point during the war. Much of the Polish resistance in its various movements not only failed to help Jews, but was also not infrequently actively involved in persecuting them...