I don't necessarily disagree with your points in general but let's not pretend as if Mourinho was just another manager at the club. We all have much more emotional attachment with him than we do with other managers. If Ancelotti or Hiddink, who we like, joins one of our rivals, think we all can still live with it because they were only here for a short period of time. But not with Mourinho. He declared himself as one of us and the fans no doubt take him as one of us too. If he joins United, City etc, there will be outrage. And I remembered some here even went ballistic at the rumours(!) that he might join United before his eventual return.