Am I reading too much into this?
Almost all of the characters are @ssholes in some way, (Axel, John, Micah, Sam, etc.) but the writers and director seem insistent on making the three main Black characters the most cowardly betrayers.
Am I wrong?
I don't think it's racism but general misanthropy : everybody on this show, their mother and certainly their pets are a-holes... If a character seems okay, don't worry, it's only because he wasn't given enough screentime to show his true colors. Think of Taka : when the show focused a bit on him, he turned out to be one major traitor to the human race, far worse than Doc IMO. Real good ones = dead ones.
On the other hand, notice that this show has more main black characters than other shows. They don't wait for a black character to die to 'recycle' him with a new black one, they introduced 3 from the get go.
The only racism I noticed was when the doctor accused a white guy of being racist because he thought maybe Muhammad was the killer since he ran off right after the first murder.
If a black guy had accused the most obvious suspect of the same thing, the doctor would have agreed with him.
So the doctor is definitely racist against white people.