Yeah its a bit harsh. I recognise that but still feel that way.
I get the not moving up part, i really do. Him not wanting to move out of wanting to compete in the champions league, or being a bit wary of our set up would be understandable and fair, I'd almost respect the player more for needing convincing. Money being the obstacle is another matter.
I just assume that whatever we're offering is probably a better deal that anyone else is willing to offer by default (officially at least). He got his current deal after leaving PSG on a free and it, along with most of the other contracts Juve were offering at the time, was inflated due to that. I dont think expecting to maintain that when we're paying a transfer fee after a mostly unsuccesful time is that reasonable. Walking away would probably be my approach too.
His time at Juventus hasn't been positive, the team has struggled, the fans were desperate to be rid of him. There aren't that many routes forward where he maintains his salary or his position in a champions league team. I dont really get why he didn't see it as a good opportunity he should make work to be honest.
And expecting enthusiasm and drive from someone you see primarily as a squad player and cover for someone better is a necessity in my opinion. Were competing at the absolute highest levels or at least seeking too. Someone going through the motions and doing enough to get by wont cut it. Its not a standard i'd apply to most, if any, other jobs but i would where United are concerned.