Was it right to cancel? No.
Was it understandable? Yes.
We don't know the background of this driver and we know uber drivers are a very diverse group of people. There are religions out there that frown upon people with deformities like they have some kind of curse.
I do know this though. Each and every one of us would of given a second thought about picking up this guy. I would like to sit here and say I would pick him up anyways, but I honestly don't know. It sounds like this was the morning but what if it was at 3am? You could easily mistake his face as a mask. Obviously now, we know his story and will pick him up, but in hindsight, the right decision is always easier.
Another driver mentioned the warts on his face could be contagious and she wouldn't want him in the same spot her kids go a few hours later. Is she a doctor? No. This driver could of thought the same exact thing.
But this driver has not been outed yet and I commend the rider for not plastering his face all over the media. (from what I have seen thus far)