Is it right for players to threatened to quit if not selected more often ?

Recently our young French midfielder Francis Coquelin has made demands for more playing time and threatened to leave the team in January should he still sees himself confined to the bench for most games. We also have the case of Cesc Fabregas over at Barcelona claiming to be unhappy but at least he did not say that he wants to leave if he is not played. Well, this has got me into thinking if this is right for players to come out public to demand for more playing time from their managers. I seriously don’t see how coming out in the media and say that you will leave if not played will help in getting more playing for the player.
The manager and his coaching team are definitely the best people to make the decision on whom to play in the game. If a player has shown great progress and is better than all his peers then it would be relatively easy deci...