I wonder if some of them are lying about it. I’ve noticed people casually lie about things all the time, including on this forum. Also people seek out a forum like this when they are pissed off. So maybe what happened (this is a made up example) is that the guest was refunded because the guest said the house smelled of cat piss. But the host reads that as the guest was pissed about the cats being there.
I’ve also wondered if Airbnb looks at the host’s entire record when deciding to refund. Do they flag our accounts with notes and then use those notes to decide? A good host with no issues gets different treatment than the host who is always calling in with some problem?