So you are the manager of one of the best club teams in the world. Not only do you have a great squad of footballers, but you also have a great backroom team of professionals supporting them.
Like any business, you know the rules, the framework of the environment you work within and you prepare accordingly.
Then with one excessively strict reaction by a referee whose job it is to enforce the rules, Robin van Persie gets send off and the game is changed. And there is no appeal, no correction. In fact if you complain you get punished.
I was trying to think of an analogy. -If you got a tax bill that was high and unfair due to an overly strict tax official, at least you would have a chance to appeal.
Having to pay a price even though you know it’s wrong, with no right of appeal to change what happened- that’s hard to swallow.