I agree that you don't have to throw out emotion to be rational. You just have to put it in its proper place. Logical analysis has to be given a higher priority in forming a good picture of events. But once you have done it, emotion is what powers your actions and words, and gives them meaning.

If I did not have millions of years of evolution making me hate death, it would be less meaningful to talk about how much we need cryonics. I would have to appeal to its usefulness in special cases (preserving great minds or useful workers) rather than advocating the abolition of preventable death. It would not be so emotional, or so urgent.

Ironically, the fact that it is so emotional is what leads people in our society to doubt it. They think it promises something they could not hope for it to deliver. Many of them have had to work through the pain of several nearby deaths already, and thus would have to question the assumptions (afterlife, nonpreventability, survival of the species, whatever) that helped them work through it to a state of acceptance.