I don’t think in general people have questioned his love for the club, but rather his work rate and desire, which is basically based on what is seen on the pitch.
I think if he was trying and failing it would be bad form, but the lack of effort is what gets on everyone’s titts. And the talk of this manager or that manager, Marcus really has gone through similar spells under multiple managers.
I don’t blame him for the wages the club gave him, but it’s a bit rich mentioning he gave up money when he’s on 300,000+ pounds a week.
United fans love academy products. So just turn it around on the pitch and you’re good Marcus.