>As to selfishness, why spend the $100k+ on having your body frozen rather than passing that along to your descendants? Do you believe that there's something special about you and/or inadequate about other people that makes your greed over a chance at a few more years of life worth the money and time you are taking from them? Is that all you think your life is worth? It's just about accruing a bunch of stuff so that you can hopefully spend it on becoming immortal before your clock runs out?

If anything is selfish, it's making all sorts of unfounded assumptions about why people choose to try extending their lifespan and then moralizing based on those assumptions. People may have all kinds of reasons for wanting to try this, and they need not be materialistic or accumulation-based at all. Ultimately, it's their personal choice, with their money, and even if they spend $100,000 on paying for it, or more, it doesn't mean they didn't leave other assets or things for their descendants.

By making a moral claim for why YOU decide that spending that money isn't justified, you're going down one very arrogant and ultimately silly road of making the same claim to so many other things people spend money and effort they've worked hard for on specific personal preferences, be they material or otherwise.
Maybe you buying a $700,000 house vs. a $600,000 house is just as idiotic then? Do you really need the extra floor space or bathrooms?

>There has always been a slice of the elite that thinks they can cheat death by doing this, and usually it doesn't go well.

It isn't just a slice of the elite that would love to have extra years of life in the face of a total unknown darkness. It's something that many people would love, and if a few with more resources are willing to pay more (and again, the prices of these services aren't absurdly expensive) to hopefully move forward a technology that gives that to both rich and poor at some point, it's fundamentally a good thing, and certainly not something that should be hammered down because of very shaky and subjective moralizing.

Where would you draw a line? Should other once-implausible life enhancement therapies that are now widely used and accepted also be forsaken? How about organ transplants? Gene therapy? highly expensive cancer treatments that all have extended life beyond what was previously "natural" for many people? Often these also start first as speculative ideas, then experiments, then just options for the rich, but later become much more widely available.

>they are also part of some weird cult, too, that convinces them that they can beat the odds. Is this time different because instead of drinking lead or drying your body, you've chosen to freeze it instead?

Let's separate completely absurd assumptions about people needing cult beliefs to be open minded on weird science from the much more straightforward and reasoned logic of wanting to live a longer life, or experimenting with interesting new technologies. Here you're just smearing for its own sake. Also, cryogenics, for all its still tenuous science, is a far cry from purely mystical beliefs like medieval alchemy. By fixating on how absurd freezing seems to you only because current medicine can't reverse it yet without damage (though nothing material makes the idea impossible), you're scoffing at the idea in the same way as a priest from the 16th century probably would if you explained completely workable modern gene therapies and organ transplants to them.