I believe that one massive pain point is that guests are allowed to create multiple accounts - if they get a bad review, they just start over.
There is no reward for them to keep the account - some time ago there was a talk about "super guests" badges and rewards, like "superhosts", but that never lifted off. Airbnb is good at coming up with blue sky ideas, and forgetting about them a few months later.
Guest, on the other hand, are rewarded by creating new accounts - they collect multiple sign in bonuses, they start with a clean slate. It is very difficult, for hosts, to ensure that the guest with "no reviews" did not play some kind of stunt before.