In a highly simplified way: total risk of insuring from theft is roughly other-risks * theft-risk, so if theft risk is 0, it means that other risks, such as insanelly high risks in asset valuation are irrelevant to the total risk which will always end up as 0.

So it makes sense that being paid to insure that which cannot be stollen against theft is risk-free money quite independently of all else. (Of curse, if something has a non-zero probability - even if tiny - of being stolen none of that holds)

I think that's the whole humourous point the previous poster was making: that which NFT promoters kept on telling us guarantees unique ownership which cannot be taken by others (and hence cannot be stollen) turns out that it can.