I personally have a problem with it for the same reason I have a problem with certain rappers.
It's one thing to be a part of something you love, it's another thing to exploit things in the interest of money.
I've only heard about 4 or 5 actual dubstep songs. I've also heard a plethora of local fan made Dubstep songs.
It was impossible to tell the difference. As a musician myself, I know how to make dubstep. I could probably be pretty successful if I became a Dubstep DJ, but I choose not to because making repetitive trippy drum patterns doesn't appeal to me.
I love hip hop music. Hip-hop can have a repetitive nature, but at least it can have harmonies, melodies, etc..
Also, Hip hop has meaningful lyrics.
I see dubstep as a spin off of techno that devaluates the genre. Techno was already a percussion based genre with little to no musical features besides rhythm.
Dubstep takes the same musicless foundation of techno and applies a loud noisiness to it.
Which I personally can't stand.
As for Miley Cyrus, and Justin Bieber, I consider them sell outs. As I do most commercial music.