ukranian and bellorussians say that the lands took by Stalin in 1939 was thier land stolen by Poland. Same logic.
Stolen by Poland from what country???==
From Russian Empire then Soviet Union.
Ukranians and bellorussians were the subjects of those above but when Soviet Union got dissolved in 1991 they got thier lands back. Certainly if Stalin didn't took them from Poland in 1939 and adjoined to Soviet Union, they got not them in 1991.
So from the points of view of Ukraine and Belorus Stalin did the right thing in 1939. Ukraine and Belorus are the most benefactors of Stalin actions.
Russia in opposite got nothing from it. But funny for you it is Russia who are resposible, am I right?:).