Ronaldo has earned the right to challenge his teammates to be better, just like he does to himself. Having accountability and understanding there's pressure to perform at United isn't a bad thing. Players have to hold each other accountable. Good teams have players who police themselves and keep everyone straight. It comes from a place of need and trust. If it isn't given properly or received properly, everyone is culpable.
That will rub people the wrong way, but also people are being challenged. Step up, have a level of tolerance, or step out.
There's always been groups within the dressing room and people with different personalities. But everyone is there to win, no matter what your role is. Embrace and accept the role and move towards winning.
Not everyone in the dressing room currently at United will do anything and everything within reason, to win. That in itself is a problem.