Not all of us want to live again in some unknown future without any sense of continuity or surviving relationships. Death is ultimately inevitable, even if a miracle like cryonics could postpone it the first time. The author's entire point is that we should accept this inevitability, not try to avoid it by any psychological means we can conjure. Only then can we respond appropriately.
What makes you say this? There is no fundamental aspect of physics that makes death inevitable except perhaps on the very very very long term (heat-death timescales).
Understanding and controlling every aspect of human biology is an engineering challenge. It's obviously extremely difficult, but we have no reason to suspect it's intractable.
If we manage to make cryonics work what tells you that people you know will not do it in the future or technology didn't make them live much (much) longer than expected? Why accept something as fact when there is an above zero chance that you can live longer?
