I think…
It actually started with artists like Vex’d, Skream, Benga, Pinch and DJ Distance. Mary Anne Hobbs show Dubstep Wars showcased it near the start of it’s mainstream acceptance. Their sound got stale and dubstep has been adopted as a moniker for all sorts of bass music.
eg. I heard Nero calling themselves dubstep on Chan 4 the other week. Sounded like trance to me just with a different bass sound.
I like loads of bass music, but don’t really give a shit what genre it’s called! (I don’t think “bass music” is a genre name. Is it?!)
([edit]also the ‘slowed down drum n bass’ thing is no criticism, as that’s how the artists described it when they started making it)
([edit] – from wiki – …in 2001, this and other strains of dark garage music began to be showcased and promoted at London’s night club Forward.[/i] 10 years it’s been going, strange the question should come up now!)