This is definitely uncharted territory. However, part of me really can't blame him because the Bills might be worse than the Browns last year, at least in terms of point differential.
Even if there they bad but you don't leave your teammates hanging like that.
It's poor sportsmanship, I guess he said it didn't even have to do with the game, but the fact that he "didn't belong on the field anymore". Either way, pretty bizarre, but at the end of the day if he doesn't want to play that is ultimately his decision. Of course, he received and should have expected the criticism.