That's because he's credited with stopping Hitler. They are asking themselves the question, "Who would be better for Russia, Hitler or Stalin?"
That's not necessarily clear cut. For those areas that experienced German occupation, there were at least some folks there who hoped they'd never go back to USSR rule. They were hoping that the Western Allies would invade Europe earlier, and would keep going clear into Eastern Europe including the Baltics, Belarus, and Ukraine. At that point, on to Moscow.