So, the reason is concern about dystopian or hellish scenarios.

The standard response to this is that you'd be much more likely to be revived by good people than bad ones - in a dystopia, cryonics would probably fail anyway, and why would they want to torture you in particular?

I can't give you actual math but I'll wave my hands at it and say expected utility is much higher for living forever in a good place. I imagine someone else is going to step up to the plate on this one.

And hey, you're going to die anyway, do you expect it to really be worse than that?