In this case, I understand there's a failure between the merchant and the buyer in not anticipating the adjustments that currencies undergo during a transaction. It would be enough for them to clearly state that the value is the value in currency X at the time of purchase, and that the same value applies to refunds.

Now, regarding Bitcoin, what was said in that message comes from someone deeply entrenched in the fiat mindset. Calling Bitcoin a speculative financial asset is proof that they don’t know what they’re talking about—either because they haven’t done their research or because they think all kinds of crypto shitcoins and their scams apply to Bitcoin, when that couldn't be further from the truth.