As I’ve posted before, I object to the word “genocide” being bandied about so carelessly. Katyn was a ghastly crime against humanity, a terrible massacre. But it was not genocide. The word “genocide” is robbed of its power when overused like this. The Holocaust was genocide, as were the Rwandan, Armenian and Herero genocides. Every massacre is not a genocide.
Poor Poles. First the Ukrainians massacred them in Volhynia and Eastern Galicia, then came the Germans, then the Soviets at Katyn.
The Croats and the Ukrainians have not reckoned with their barbarity, either, nor have the Turks.
You fail to mention the holodomor. Soviets responsible for katzn were still receiving their pensions even after the Russians admitted they were responsible. FDR was informed that the Russians were responsible and he sent the informant to Samoa.