I think the media covers Justin Bieber fairly and objectively. If he behaves like a bad boy, he gets treated in the media like one. If he has a great performance, the music critics give him a good review. If he gives a bad performance by lip syncing, not dancing and just generally looking bored and tired, he gets a bad review.
Basically, I believe the media calls it like they see it so to speak, and I think that is how it should be. Just because he is a superstar, doesn’t mean he should be treated no better or no worse than anyone else.