Justin Beiber just has a very hate-able persona. I think his handlers are trying to pass him off as being the bad boy. Especially with the rapper persona. He's certainly got the rapper personality, mixed in with plenty of spoiled rich twat; flaunting his wealth, and generally being a dick to everyone. Not to mention that he has zero talent.
Every generation has their own idols. The problem with Beiber is he's only got a short time left. Once his current crop of fans grows up, that's it. The next group will find someone else. I don't think he's the type that can fade and he doesn't have the talent to stretch out beyond being a teen idol, like JT did. I can see him crashing and burning hard. My bet is by age 22, he'll be washed up. Then the real fun begins. I'm guessing it will all start with a DUI and go down hill from there. Always does.