Classic example of a 'problem' that is the creation of the club. Do not get me wrong, I love the boy. His story is deeply moving and his principles and values have rightly set him apart from many others who rise from poverty to extreme wealth, but who never forget that they came from poverty.
That said, the idea that 'Rashy' wants to go somewhere where he will be guaranteed first team football, only serves to underline the sort of culture that has been allowed to flourish at United. Some of our players believe that they are bigger than the club. They believe that first team selection is not a right to be earned, but rather a entitlement, which they should be guaranteed. Under Sir Alex Ferguson, Rashford would likely have trodden the path of McGrath, Sharpe, Ince, Beckham, Keane et al. Players who ultimately thought they were too big for the club or who Sir Alex thought had become unmanageable.
There is simply no room in football for sentiment. If Rashford's performances do not merit a first team place and he is not willing to stay and fight for one, then I would hold the door open for him as he leaves. Terribly sad that it appears that he is unwilling to roll up his sleeves and play for the club that has helped give him the amazing platform to play the game he loves. But, I absolutely would not want him to stay out of some guilt trip.
Likely that his handlers and hangers on have his ear and he is more inclined to listen to them than anyone else. Enough is enough. Let him go.