Concerning the idea of people's musical taste, people will listen to artists they like, music that already mirror the things that make them them. I don't care enough to list reasons why I don't like Justin Beiber (I wouldn't go as far to say I hate him, though - he doesn't even deserve that), but in all reality, he's just a kid who struck it rich and has no idea how to deal with his ego, power, and fans.
Oh ho ho, but Blood on the Dancefloor. No. You cannot tell me they are decent people. You can't. You can look at "this":http://superwidget.wordpress.com/2011/05/16/blood-on-the-dance-floor-a-cold-calculated-review/, for a more coherent and logical reason why I just cannot. Yeah, no. Just - no.
-S