Post-translational modification of proteins is involved in some types of memory. Sustained post-translational modifications are likely to involve changes in gene expression. Otherwise, the system would not be very robust.

Changes in gene expression are likely to involve changes in the cell's epigenome.

Even if the post-translational modifications are gone after you replace water with cryoprotectant, the epigenome might be still stable. This would allow you to see what the changes in gene expression were. So, you might be able to tell what the memory was.

This is not a new idea. Ben Best:

Considering that the structure and function of Aplysia neurons are so similar to vertebrate neurons, it seems quite plausible that memory is stored by increasing synapses, increasing active zones and increasing transmitter vesicles at selected neurons in the brain — although we must await definitive proof. Assuming that memory is stored by this means, it seems unlikely that cryonics procedures could be perfected well-enough to preserve short-term memory, but avoiding structural damage to synapses and the active zones of synapses may be adequate to preserve long-term memory. It is probably even more important to preserve the state of the transcription regulator proteins in the neuron nucleus — such preservation may be adequate for reconstruction even if the synapses and active zones are lost. It may be even more difficult to reconstruct the state of the transcription regulator proteins from the number of synapses and active zones. The "redundancy" of information may be very valuable where there is partial destruction of both the transcription regulator proteins and the synapses.

You also say:

Is either meaningless or flawed, probably both

It could definitely be flawed. We don't know. That's why I used two conditionals in the sentence you quoted.

The whold post reminds me of the idea on LessWrong that one might as well just assume Omega will reconstruct you based on trace evidence in the physical world.

What part of

It's also important to stress that this only occurs under ideal conditions. Given the current practice of cryonics, cryoprotectant will not reach many or most areas of the brain. In these cases, there is a large amount of ice damage and the information is much more likely to be irretrievable.

did you not get?

I have little idea what it is trying to argue.

My main point is that kalla724 is too pessimistic about cryonics. We don't have a lot of answers to important questions and therefore can't say with so much confidence (p = 10^-22) either way.