Russophiles will try to contort just to make it appear that the USSR had no choice but to embrace Hitler in 1939 or that the West compelled Stalin to make the embrace (Oh hu hu hu.... lame), but they cannot erase the fact that the USSR was the only non-Axis country that had a 10-year alliance/pact with NAZI Germany. The USSR by giving assurance of non-aggression to Hitler in 1939 help start WW2. Of course since it help start that war it's only natural that it share a bigger burden in helping end it....
BTW, the USSR even had a neat economic agreement with Hitler that supplied NAZI Germany with raw materials that no doubt were used in waging war across Europe. Ironically, the same raw materials may have been used against the USSR in Barbarossa...