The premises of Pascal's wager are normally presented as abstract facts about the universe - there happens to (maybe) be a god, who happens to have set up the afterlife for the suffering of unbelievers.
But, assuming we ever manage to distinguish trade from extortion, this seems a situation of classical extortion. So if god follows a timeless decision theory - and what other kind of decision theory would it follow? - the correct answer would seem to be to reject the whole deal out of hand, even if you assume god exists.
Or, in other words, respond to a god that offers you heaven, but ignore one that threatens you with hell.
The notion that God might be evil is not a mere "strawman"; it is in fact a feature of some actual religions, notably Gnostic Christianity. Of course, the Book of Job in the Hebrew Bible seems to aim at refuting this very argument, since it freely admits that God often appears to be evil from our point of view; but since he is infinitely wise and knows so many things which are entirely beyond our understanding, and has done plenty of nice things for us besides (such as laying the foundations of our very world), how can we argue against his goodness?
Viliam's account of a "supernatural Stalin" was in fact a strawman. It is not even equivalent to the evil God in gnosticism. The gnostics thought you were supposed to reject that God and not do what he says; you definitely would not say that he was good. In contrast, no one believes Viliam's theory, and so it was definitely a strawman.
It is also strawmanning, although less indefensibly, to imply that modern religious beliefs are equivalent to ancient extinct ones.