based largely on anonymous testimony

"Based largely"? Are we reading the same page? I see plenty of papers, articles, FOIA lawsuits, TV programs, quotes from published bylaws etc.

The point is, why do they believe that cyronics is pseudoscience in the first place?

Yes, that's a good question, especially when their original criticism - exploding lysosomes - is now on the ash-heap of history, and when their entire field demonstrates the success of cooling and vitrifying techniques. One you don't answer.

Mike "Darwin" says that it's because they are prejudiced and they have a personal grudge against him, but that sounds quite unlikely, expecially given that, as even he claims, cryobiologists have been indifferent or even supportive of cryonics in the early days.

Really? Let's look at what Darwin himself wrote in response to this exact question:

But beyond this particular incident, it is clear that the Society had a long history of less focused enmity toward cryonics. What was responsible for this enmity and lack of cooperation between cryonicists and cryobiologists? The answer is: a lot of things.

'A lot of things'. I see.

What likely happened is that the evidence that cryopreservation of whole human bodies (or heads) was not viable accumulated, and cryobiologists did what proper scientists are supposed to do: discard the failed hypothesis. Mike "Darwin" and his ilk, on the other hand, clinged to it like the homeopathists inventing stories about "water memory" when they learn about Avogadro constant.

I don't have the expertise to evaluate all the technical claims in the article, but Mike "Darwin" lecturing cryobiologists about cryobiology sounds like creationists lecturing evolutionary biologists about evolutionary biology.

So you haven't bothered to read anything that Darwin has produced carefully, as demonstrated by your repeated mischaracterizations, you know the cryobiologists have been either wrong or lying about why cryonics wouldn't work, and your best guess is to compare cryonics to memory water and creationism.

If I have to apply the authority heuristics I'm certainly defaulting to the mainstream authority, not to some guy who sells a fringe practice that (a) appears to be unviable in the light of my knowledge, (b) looks very much like a religious ritual (c) has been the subject of confirmed scams in the past, and is now offered by questionable organizations.

Darwin isn't selling anything now; and I've asked him what he thinks of that particular 1991 essay of his, and he mentioned nothing like 'oh, I made all that up so I could sell ALCOR memberships' despite his fierce recent criticisms of CI and ALCOR.

Does that make you take him any more seriously and in favor of cryonics, or are Darwin's criticisms just going to go through your one-way filter and come out as 'cryonics is bunk, even Darwin says so!'?

( * why this guy doesn't use his real name instead of trying to hijack the reputation of a great scientist? It's like calling yourself Einstein or Newton)

People change their names for all sorts of reasons; for Darwin, it's admiration for the original back when he was a kid and defending Darwinism against Creationism, not 'trying to hijack the reputation of a great scientist' although perhaps he was an unusually foresighted kid and adopted the name so decades later he could fool people into thinking he was someone from the 1800s?

(Which by the way is really ironic, since you're the one comparing cryonics to Creationism! Why are you including such a lame criticism, anyway? Do you want people to dismiss you out of hand for ad hominems?)

It's like calling yourself Einstein or Newton)

This seems denotatively true.

( * why this guy doesn't use his real name instead of trying to hijack the reputation of a great scientist? It's like calling yourself Einstein or Newton)

Well, I hadn't suspected that that wasn't his original last name.