. . . .in the Soviet-occupied part of Poland, Polish intelligentsia perished in Katyn and in the Gulag. Twenty-one thousand were murdered at Katyn, Bologoe, Dergachi. A million and a half went to the Siberian gulag. Show me another nation in Europe that suffered the fury of two of the most murderous regimes in modern history.Yet even in these circumstances, at least one million people were involved in sheltering Jews (Lukas 150). In these circumstances, everyone of them was a saint, a hero, deserving no fewer accolades than Raul Wallenberg who was sheltered from Nazi retribution by his nationality, wealth and social status. In contrast, Poles who helped Jews were protected by nothing. . . .
It has to be said, bluntly, that while the interests of Jews and Catholics were the same concerning the Nazis, namely, the Nazis were a sworn enemy, in regard to the Soviets these interests did not coincide. For the Jews, the Soviet Union was a possible refuge from the horrors of Nazi occupation. For all too many Jews, the Soviet Union was a land of promise.
A significant part of the secular Jewish community in Poland greeted the Soviets as friends and collaborated with them in every way until the mid-1950s, thus contributing mightily to the destruction of Polish economy, culture, and population. Similar things could be said about the Polish-Soviet war in 1919, when mendacious gossip of "pogroms in Poland" was spread by Marxist and non-Marxist Jews in the West, to prevent the creation of a non-Marxist independent Polish state (Norman Davies, God's Playground, vol. 2, Columbia 1984, 262-3). In contrast, for Polish Christians the Soviet Union was, from the beginning, the country of the Gulag, a sworn enemy bent on destroying the Polish identity. . .
In Revolution from Abroad: the Soviet Conquest of Poland's Western Ukraine and Western Belorussia (Princeton, 1988), Professor Jan Gross says: "For the record, it must be stated unambiguously" that when the Red Army attacked Poland, it was welcomed by smaller or larger but, in any case, visible, friendly crowds in hamlets, villages, and towns. These crowds were largely Jewish . . .
http://www.ruf.rice.edu/~sarmatia/498/thompson.html
Most Jews living in what became eastern Poland during the interwar period were born in what had been Russia and were raised as Russians since Poland still did not exist prior to WWI. They probably did welcome the Russians back because the area had long been Russian and they did not think of themselves as Polish. My mother came here in 1910 from an area that was then in Russia but was in Poland between the wars. She always thought of herself as Russian.