Holocaust historian here. This is a very complex and loaded question. What does the term "collective responsibility" mean? There are absolutely individuals who were Poles and Ukrainians who worked with Germans to kill Jews, or as guards at concentration/death camps. (Which means they were part of the system that was set up to murder Jews). There was also an unquestionable legacy of racial antisemitism and Christian anti-Judaism that existed in Poland and Ukraine prior to WWII, which the invading Germans were able to tap into once they arrived. There are also many examples of inaction on the part of individuals or groups from both Poland and Ukraine, when it might have been possible to help save some Jews by taking action. But it is also a fact that the systematic mass killing of Jews did not take place in either location before German forces arrived, which suggests that the ultimate initiative for the Holocaust came from Germans.

What is 'collective responsibility', and how is it measured? This is a strange question, but I can attempt to answer it from the Polish standpoint.

There were no Polish-run concentration camps and no Poles with real power in the Nazi hierarchy. I personally do not think it true to say that the Poles as a group had much responsibility for the Holocaust. There is somewhat of a contradiction between books I've read about how anti-Semitic Poles were at this time, but there is an agreement that the Polish were not truly anti-Semitic until the 60s, when the Holocaust was distant, the Jewish population was nonexistent, and the Soviets had fully permeated the government. Despite this, I will concede that nearly all escapes from Nazi concentration camps were conducted entirely from within, and it could be argued that Poles did not do nearly enough to help those who were in far worse condition than themselves.

Overall, this question comes down to whether it is logically sound to decry the inaction of Poles and Ukrainians as a subjective action in support of the Nazis, which is a different debate entirely.