There is absolutely nothing wrong with what Mourinho has said re: Valencia, if it has gotten to the stage where a manager can't say anything negative about his players at all without receiving some sort of backlash, then I'm not quite sure where football is heading. He also has a right to be pissed off, regardless of whether a player has won the WC or gone deep into the competition, if they truly believed in what Utd are trying to achieve, they would be coming back early to give their manager a dig out.
Whether this is due to Mourinho breaking down these relationships to that point is the cause is another matter, but you can see from his perspective why he is angry about it.