My thought was that is was that the guest always gives low star reviews.
I noted this line in the email from John in support:
This is what Patti posted a few weeks ago once she got the reservation:
If Airbnb could see that she is giving 1 star reviews to hosts who usually get 5 stars and there was no problem reported during the stay it seems like an easy call to take the host’s side. Even as guest friendly as Airbnb is, this unstable guest isn’t doing anyone any favors.