I don't buy this swings and roundabouts argument at all. Refs make mistakes, that's only natural and most of the time, they are close calls, only cleared up with the benefit of slow motion analysis after the game. Or in Arteta's case against QPR, left inconclusive. In the heat of the moment, the ref has to make a decision, so you can understand why they sometimes get some wrong.
But the incidents of favouritism towards Utd are now becoming far too frequent for it to be a coincidence. Whether it's deliberate bias, subconscious bias, fear of being lambasted by Fergie - and his media loving lackeys or just poor referring, something has got to be done about it.
Clattenberg yesterday was diabolical. He made mistake after mistake and then tried to correct his mistakes with more mistakes. The fact that he's also being complained about for making racist gestures is just the icing on the cake of a terrible day for referring.
I would never want to face Utd with Clattenberg or Webb referring and I suspect that most fans would feel the same. Their bias has become all too obvious now. It's time the FA took action, because it's ruining the game.