Even without the ethical crisis, there are simply going to be situations where the true facts are simply unknowable to a customer service rep. So, do you screw over the person providing the property (who may in fact be a lying scumbag)? Or do you screw over the other person renting the property (who may be the lying scumbag)? (Or may simply have utterly unreasonable expectations.)
And, yes, my understanding is that eBay evolved to simply default to the buyer being right.
So what do you do?
AirBnB without listings is like eBay without listings. (Though I've generally heard that eBay tends to come down on the pro-buyer side)