I certainly don't want to have a quarrel about Airbnb, but I also don't share your enthusiasm with it, though I agree they seem better than the competition (or 'less awful', as I put it).
My experience with their "customer service" has been terrible. The reps seem half-witted. Much of the time they don't seem to understand what I'm saying. I meant to post one extended exchange I had with them, but haven't got around with it. And that's on Twitter, where at least they reply. Via just email my experience is that they don't even attempt to address what you write. Why that is so, I don't know. And they tell me they will follow up on stuff, but don't.
I've not had to contact them over any real issues yet. So I don't know how that would pan out.
Also, their web site seems to have a lot of problems.
But I can believe they are better than their competitors. Booking.com certainly sounds awful.
I don't know why our experiences have been different. Of course, you've been doing this much longer than I have. I just started.