In the Cowboys-Giants game...?

Did you see the segment where it was like 3rd&10 in the 3rd quarter and he screen-pes it to barber, Then when Marion Barber is running the referee is jesturing with his hands "COME ON COME ON", I thought ref's weren't allowed to show liking to a team in a game. I though they were supposed to look netural. I understand they have the right to like a team, just not show it in a game.