The most popular 'pop artists' are simply the easiest to pick on because everybody has heard about them. I personally believe that it's not so much bieber/gaga etc. but just record companies in general that are the culprits, and in my eyes they've basically killed 'real' music (for the sake of discussion I guess I'd call real music the kind that doesn't have auto-tune and scripted live shows that are more about the dancing and costumes than the actual music). It's easier to say "Man, Justin Bieber really sucks" than it is to say "Man, Joe Blow, the head of Sony BMG, really sucks" because no one knows who that guy is.

They give you singers like Kesha and T-Pain who actually make their money from having voices that are obviously auto-tuned and on the other side of the spectrum you're given a band like Kings of Leon or Paramore who are presented as your only non-pop alternative. Then actual hard working bands have to work twice as hard just to make it to a point in their career where they may be able to make enough to survive off of their music. Justin Bieber didn't deserve to be discovered any more than probably 1 million other 'actual' bands that have put themselves on Youtube.

And Marilyn Manson, despite whatever stylistic choices he may make, has a voice that could probably strip Lady Gaga of her skin, and I'd probably say that to anyone who was trying to compare the two.