The whole Martial FC comments coming from some posters don't realize just how much they sound like Mourinho/Rashford FC themselves. To not comprehend how some have an issue with Rashford starting almost ever PL games (which is the priority this season) and that Martial should be happy being the player of the month and coming off for 20-30 minutes at the end of games and get his starts in the CL is simply being dense. There are some pretty clear case of Mourinho screwing up in recognizing the talent he has at his disposal which resulted in losing those players, as well as eventually getting fired down the line, with the club regretting no longer having those players.
Without a much more balanced rotation where Martial can start more in the Premier League, whether it's instead of Rashford/Mata/Mikhi, then I have no issue with him looking to force a move out, especially if his current situation winds up costing him a place in the world cup. It is still early, but there's already shades of mismanagement by Mourinho in regards to Tony. Mou is obviously dangling a carrot in front of him but if his current performances already have him over a thousand minutes behind Rashford in total playing time and it's not changing soon, I think Martial will tell him where he can stick that carrot and find an alternative. One player shouldn't drastically change a coach's gameplan; if it does then it's the coach's fault, not the player. There are more difficult jobs in football than winning by starting Martial and/or Rashford in a more balanced way so you keep everybody motivated instead of clearly favoring one who really doesn't bring much more than the other at all, or even worse rotate the two for Mata or Mikhi who have had very inconsistent games despite Mikhi's assists.