You are right he's not United fan first and foremost and few players were before they joined. Thing is, once they joined, unless they have issues with the club/manager/colleagues/staff/or family issues etc, they should shut up and play their best for the club. It's not like they were conned into signing and suddenly remember/informed they are not playing in Europe this term. I see many thing wrong with being "honest" "outspoken" and predicting the future when he's only been here a few months.Not surprising and it's better to be honest. Atleast it was clear to me while the transfer unfolded that he indeed wanted Psg at the beginning for whatever reason and it's perfectly normal. But even in this interview he does mention the perseverance of United actually made him choose us. I don't see much wrong really, he is not a united fan like you and I who dreamt of only playing here. We are also not giving him European football which a player like him deserves. He is a smashing player and we should get the best out of him for however long he stays. When he moves, he moves. Things change fast in modern football, a year or two down the line Adm could completely be a united through and through or looking to change clubs. But, it's hardly out of the ordinary.
If LvG did not see this as an issue, I think he had better rethink and reassess his own management style why he has all these quality players on paper and yet we are now close to mid table and Christmas is almost here. Sigh