Given that c. elegans survived vitrification, it's not surprising that its memory persisted, though it does underline the point that memory is not some kind of magic - it's physically recorded. Of course large mammals like humans are very different from c. elegans.

Given that

• humans survive immersion in freezing water and 60 minutes of brain death with their memories intact
• c elegans survives full vitrification with memories intact
• connectome information and intercellular structure survives aldehyde stabilised cryopreservation

we can conclude that the skeptical case is trying to thread through an ever narrower gap. If you claim that the physical correlates of memory are too delicate, you contradict existing results. If you claim they are too robust, you are forced to conclude that they are preserved by the best cryo.