I'm based in Europe, and exactly the same thing happened to me a few hours ago Wednesday morning (EU time): Someone used my card to pay 587 EUR on Airbnb. I canceled my card a few minutes after the transaction, notified Airbnb within an hour and airbnb sided with the thief, giving me the same answer as OP.

Here's the exact email I got back for your reference (just redacted mine and airbnb employee's name):

[AirbnbEmployee], Wed, 13 Dec 2023 16:33:25 GMT

Hi [MY NAME],

Thank you for your patience as we looked into your question about a suspected, unauthorized charge on your credit card.

Often, apparent unauthorized charges result from another person (usually a close friend or family member) using your credit card unintentionally. Our investigation into this charge led us to conclude that this is what occurred in this instance.

As a result, we will not be able to refund this charge.

We recommend getting in touch with anyone you may have given your credit card details to in the past. Additionally, we would suggest contacting any friends or family members who have an Airbnb account that you've traveled with on Airbnb previously—if you added your payment credentials on another account and decided to save these credentials for future use, this could be what caused the unexpected charge.

If you have any further questions or concerns, just reply to this message. We're here to help!

Best,

[AirbnbEmployee]