Dubstep it annoying, but to each their own. By saying dubstep is just smashing keyboards and shit is not entirely true. As a drummer, I can respect some of those beats. I think dubstep is limited on where it can go as a genera because it pretty much all sounds the same, but I wouldn't be so quick to discredit it as music, because it is music, it's just not typical.
The only argument that I would consider making, would be that the mainstream music outlets and journals shed some light on music that IS not fucking garbage. It blows my mind that some of these bands that are screaming and being all pissed on stage with chains and eye makeup on are selling shit. They're selling a fucking image, not a sound.