I think it was a yellow card worthy offence and some immaturity on his part, after getting the better of Ribéry at every occasion. However, I think the referee was going to give Rafael the benefit of the doubt and a talking to, before Bayern hounded the ref and basically forced him to make the decision. This is what United fans are more bitter about, not the fact that both offences weren't card-worthy. Bayern also manipulated the decisions of the referee all game, watch it again, they were dropping like flies at every tackle and the vast majority were never fouls, not in a million years. To add insult to injury, van Bommel was given the benefit of the doubt after he was already booked, after shoving a United player to the floor. It was as blatant as Rafael's foul, so why was he not sent off?
It's just such a lack of inconsistency that seems to be happening for too consistently on most referee's behalf. The sooner we get a Video Official, the better. It's ridiculous.