I didn't watch the game but watched the highlights on Motd2. How is Taylor allowed to referee the team he supports?
Even ignoring the penalty, (which I am not sure City would have been given?), he effectively gave United 2 goal assists.
For their second Maquire bundled Abraham over on the edge of the area and he waved play on.
Then for the last goal Zouma, the Chelsea cb, was down in the United area with a head injury, many players were shouting to put the ball out of play to allow treatment, and he ignored it to allow United to play on and score on the break.
Why are you still questioning this? Surely you know the rules by now?