I suspect Schiavism plays a large role in holding back changes in attitude and legislation regarding cryonics, assisted suicide, euthanasia, but also medically assisted procreation, contraception and a host of other issues.

The views of Leon Kass, Bush's bioethic's chairman, were particularly odious examples of this attitude. I'm not sure if he has attacked cryonics, but I've read attacks by him on every other item on your list, and on non-cryonic life extension as well. As nearly as I can tell, he opposes anything that extends people's choices.