Pretty interesting that so many people are able to take the high ground when it's not their contract, their job or their life. Very easy to come out with stuff behind a keyboard with absolutely nothing riding on it while taking a dim view of someone else.
I don't see that he's doing anything "wrong." His position may be that he doesn't really want to leave Manchester United and is okay to compete for his place, rather than wanting to leave and trying to have his cake and eat it. Maybe he's saying that he will concede that the manager and club don't really want him and will move on if the club is inclined towards that, but to do that he doesn't want to take a hit on a contract we put in front of him and both parties signed. If it is the choice between losing out financially or staying, he may be saying he would rather stay. There isn't any real contradiction within that position whatsoever.
Ultimately, don't have a go at him for being reluctant to leave the best contract he'll ever have that all parties were all too happy to place ink on. A compromise is probable, but it's not Harry Maguire that's the bad guy, it's not his fault we paid too much for him both on transfer fee and wages and now we're scrambling to reach an acceptable financial package that sees his departure. It's all very much part of the same balls up made by Woodward and Ole and co. If we didn't pay 80 million we wouldn't be on our arse trying to get a book value, we probably would have been able to justify a more acceptable salary package rather than making him a record signing and having to follow through on that, and ultimately if we'd have scouted better in the first place we'd never even have proceeded. So it's our mess that is being cleaned up, not the players.