Welcome to a world where everyone is judged to be equal to the lowest common denominator unless proven otherwise. Do you have a lock on your front door? How do you determine who you invite into your home?
Enabling discriminative behaviors does not mean using discriminative behaviors. It’s called freedom. Judge people by their actions not by what you think they are allowed to see by a gatekeeper.
This is horribly gamed. Host/renter give each other good ratings. Or neither rates because neither is sure what the other person will do so they wait for the other in a stalemate.
It creates a gatekeeper that enables discriminative behaviors.