What do people expect?
The amount of money in the modern game and the value of these players has made them infinitely more valuable than the managers. This money has attracted vulture-like agents that are constantly in the ears of the players, influencing their every move in a society driven by a mass media that thrives on controversy, in a culture dominated by self indulgent egos and a demand for serial publicity. Players were once slaves to the game; now it's the other way around, and it's a damning indictment of the footballing powers that have allowed it to happen.
With regards to Pogba himself; the guy was an integral part of a side that has just won the World Cup, he's almost certainly our most talented outfield player, and he showed as much in the first game of the season with only a few days of preseason training under his belt. Disregarding the power struggles within the club, his recent statements laced with contempt at the club's hierarchy, and the cretin that he associates with, Pogba still deserves to be paid for his worth, which to this Mourinho side, is much greater than Alexis has proved to be.
If he wants to leave the club, let him leave next summer and put plans in place to replace him directly, or change the way we play in advance of his transfer. I can understand his frustrations with this team and the restrictive approach of it's manager. I can't say it would appeal to me much either. Of all the players on the planet, I'd suggest that Pogba is one that needs to feel the enjoyment of self expression more than most.