I drove for Lyft one summer and someone who had just gotten into a serious motorcycle accident called me to take them to the ER. They bled all over my back seat, not to mention terrifying me because I have absolutely no training as a first responder. If you need to urgently go to the hospital, call a fucking ambulance, not an Uber!
Does that change the fact that the driver has to clean your virulent vomit? You might come away with a 5 star rating if you apologize and paid for the cleaning, or if the driver felt sorry for you.
It is just that there is a difference between deliberate or avoidable bad behavior and situations where one cannot help themselves and need the transport system for emergency rescue.
It is crazy the latter could land you on a blacklist. A rating system is not necessary. A reporting system for the rotten apples would suffice, and the rest of the customers would be unrated.
The guy brought to hospital may end up in coma. Not able to clean up.
With reporting you cannot have a pissed-off driver land a pregnant women on a blacklist because she delivered her child in the car, and there is now blood on the seats.
There is some occupational hazard for taxi drivers and others in public transport. The provider company or insurance should cover cleanup costs.