So, you've noticed you are confused, and concluded that the false belief must be "the anti-aging community contains a non-negligible number of rational munchkin types", rather than "storing tissue samples is cheap, flawless, reliable, and useful"?

You say you've asked loads of people. What did they say? "No, I didn't do that. I dunno why."? Did no one have an explanation like "I hadn't thought of it" / "I never heard of it" / "It's poorly advertised and I don't know who to call" / "It's too expensive for too little pay off; let's fund cryonics / rejuvination therapy instead" / "It doesn't actually work the way you think" / anything at all? It sounds like that's what you're saying, but did no one at least try to rationalize it? Even with "That sounds dumb" or just laughing it off?

Not even one rationalization, even a feeble one?

That seems unlikely.

Not just "I'd expect people to be smarter than that", but "I'd expect people to make at least a tiny effort to justify their preference when it is called into question, even if by just saying 'that is my preference'". Maybe your responses were mostly noise, but what sort of noise?

If it's just that people haven't even heard of it, then clearly the solution is to raise awareness. If it's that people aren't getting sufficiently excited, then the solution is to do our own cost/benefit analysis, and if it still works out in favor of tissue-freezing, raise awareness of that.