This is a good illustration of how hucksters and differentiated meme virulence mean we can't have nice things.

People really want X (e.g. to live forever, to lose weight, etc.). Hucksters take advantage of this by promising X, and memes that persuade people they can achieve X by adopting the meme (e.g. Christianity in the case of living forever) spread. Then people develop antibodies to the hucksters or memes, and the antibodies end up attacking anything that promises X (since it resembles the mistaken claims).

As Randall Munroe joked:

Somewhere out there is a company that has actually figured out how to enlarge penises, and it's helpless to reach potential customers.

Hence my proposed slogan for cryonics, "Cryonics: A scheme for living forever that might actually work". Of course, we should only use the slogan if it might actually work, which looks highly doubtful to one LWer who is a neuroscientist.