If someone could freeze at least a small insect brain after it "learned something", unfreeze it and prove that it retained what it learned, I might have at least a grain of faith in this. Even getting an insect ganglia out on a feeder plate with electrodes, training it to respond in a way to a certain sequence of input electrical impulses and proving that after thawing and reanimation it still preserves that memory would light a spark of faith, but we don't even have this!
Understanding "biology 101" means understanding that biology is about experiments, everyth is empirical (and will be for quite some time I guess), nothing can be said that "it works" in biology or medicine until you experimentally prove it does. Maybe in a few centuries we'll have cool equations describing life and have something like "theoretical biology" that will be like theoretical physics is to physics (no, what we call "theoretical biology" nowadays is not that!). Show me some equations (derived from experiments, of course, and that can predict other experiments of course) describing the amount of information relevant to a human's personality that can be recovered from a frozen brain! If you can't, prove it experimentally. If you can't... bad luck! With the kinds of probabilities involved in biology, "good things" (like being lucky to be able to revive a frozen human brain) don't happen by chance!
"Nature"/"The universe"/"God" is NOT on our side on this path, so there's no room for optimistic thinking, we can only rely on cold (literally) hard science and math!