Maybe Amorim is a good coach and sees how to make Manchester United better, but he is clearly limited in funding for new transfers. And maybe he is also right about the players he wants to sell, otherwise the team would be stronger, but if he came to such a team, he should have assumed that it would be difficult, because when he came here he saw that the club was doing very badly.
Personally I have never doubted the ability of amorim so I believe whatever decision we see him taking is for the good and repositioning of the club, that area of funding is where the problem is, but if Manchester United management can provide funds for him to shop for all he needs, I somuch believe in his abilit.
As for those players he wants to sell of course he knows them well, he has been with them in the just concluded season, he undertands that they don't fit into the club play pattern again or they are not in good form and keeping them might cause the club a lot harm than good, so the best option left is to sell them, building a clun that was once good and later became bad requires a collective effort from both the management and the manger himself and I think the time for them all to act if they want to get it right is now.