He posted a mocked-up picture that was doing the rounds at the time of Webb in a United top. I don't think he talked about bias though. I think he commented that the media consensus that Webb was the best referee was a joke. He later apologised which didn't stop him picking up a sanction from the FA.
I know you think they are different but do you think that's more or less serious than Rio's tweets on the choc-ice comment about a fellow professional?