A possible reason is that, even though Stalin was nigh-omnipotent in the USSR, he did not create it, and he did not put the people there.If the biblical and pre-biblical creation myths are to be believed, then the God of choice, in this case, the Judeo-Christian God, did create the world, and he did put the people there. His universe, his rules, so to speak. Of course, that just means that we have free will, but we have no choice if the assertion that hell exists is correct. And free will with only one possible choice doesn't sound that much like free will to me.