He didn't seem to be in the right mindset for the interview. His voice sounded shaky. The interviewer was a bit pushy with the Timberlake thing and fair enough with Bieber's response to that, but the whole mother thing was too far, from both sides.
The JT comparison wasn't the cause of him hanging up the phone. It was the point where the interviewer asked him does he worry about Harry of One Direction around his mother since Harry loves older women. Justin took that as an insult and dissed the interviewer's mom, who's dead.
I don't think he's really ready for this yet. He has become notorious for these incidents. I started to notice this when he lost Best New Artist to Esperanza Spalding and he really didn't seem like a good sport.
The Beliebers didn't take it well either, its a shame they actually thought he was going to win
I hang up on people all the time. If someone asks me such a STUPID question about my mother, I wouldn't have a desire for this conversation to continue and clearly Justin was offended and retaliated but his retaliation backfired once he finds out the man's mom is dead. What else could he have done? Apologized? Why would he want to apologize when he was very insulted by what the Mojo said. When you get offended the LAST thing you wanna do is apologize to the person who insulted you.