"Just the facts, ma'am".
Airbnb customer services only responds to facts and evidence. It happens with guests all the time. It's actually famous. Download a photo of a cockroach, make a complaint to Airbnb, send the photo. Voila! Refund.
Unless of course, the host can provide reasonable evidence of it being fabricated (e.g., the photo shows a floor covering or other things that the house doesn't even have).
The same can be true in reverse. The host may have had damage from a previous guest, but for whatever reason, failed to make a claim or couldn't be bothered. So, blame it on the current guest. Yes, it's absolutely wrong and unethical to do this, but unless you can prove otherwise, Airbnb will stick you with it.
So, a lesson: if there's damage when you arrive, take photos (preferably with date and time stamp). Send it to Airbnb and tell them you don't want anything from the host, just to put it on the record, in case you get blamed for it. They won't contact the host unless you say you want something, so make that very clear.
I know, you shouldn't have to do that. But that's how "aircover" works. It doesn't necessarily have much to do with the truth. Only what one side or the other can prove and/or disprove.
In this case, your best and only defence really, is to write it in your review of the host. Trying to get Airbnb to reverse it is mostly futile and will waste days or weeks of your time.
Other platforms aren't quite as interventionist as Airbnb, but they also don't really care either.. So just be cautious with any platform.
Good luck...
