As much as I think that wes can be condenscending, metal tones are affected by the guitar and the way its built, pickup selection and wood types.
I've been playing metal for too long (I don't want to date myself here... LOL!) and I can hear the difference between Maiden, Priest, Rhoads, Iommi, Metallica, Megadeth, System of a down, Killswitch Engage, Dokken, and the list goes on and on....
Maybe its just a question of liking/disliking a certain style. To some, all rock & roll sounds the same. To some, all opera sounds the same.