I just watched this after my recent re-read of the novel. I was pleasantly surprised. It is good and faithful. But there is some modernization and minor changes which serve to translation from novel to movie. Overall I think it is really faithful to the novel.
I don't get why people didn't like this one. Maybe it was the lead actor being black or USA being shown as a totalitarian state. Also Netflix original movies are being generally disliked. People are such a chorus of parrots if there is already a strong consensus about a movie. That's my guess about low rating.