Even if Justin Beiber himself is clueless (and I don't think he is), the people around him are experts at creating a product that appeal to their target demographic. The most successful stars that, to you, seem to create shitty music are those that actually have the most clever people handling them.
I would classify his handlers as manipulative, not clever. I would classify Justin himself as clueless, largely due to his apparent immaturity that he constantly exhibits, but I'm sure he'll be pretty sharp when he grows up. We were all young and clueless at one time.
As for my previous statement, it was mostly a joke.