CAPTAIN CAVEMAN

Your ignorance is shameful. You seem (and I'd be willing to bet on it) to have little to no experience with any small subgenres, and because you have not experienced them in depth, you obviously will not understand the importance of their existence. Of course, it will just be a word to you, describing something you do not understand, and you will eschew it as being ridiculous or unnecessary.

But consider this analogy: you are a child, you have a small vocabulary. I describe a man's demeanor as wrathful, a word you do not understand. I tell you that it means angry, and you say "well, why not just call him angry?" I explain that the word wrathful has connotations which describe the man in more depth than simply "angry". Yes, he is angry, but more specifically, wrathful. So it is with genres; yes, Metallica is a rock band, but more specifically, metal; even more specifically, thrash metal. To go back to my example, I could say the man was "silently wrathful."

Genre is a descriptor as necessary to music as colour to anything we percieve visually.

And I can't even believe that I even need to point out that "good music" and "bad music" are completely useless for description, and to say that "there's only awesome music and not-so-awesome music" is like saying there are delicious apples and disgusting apples. Yeah, so what? We know that. You have to describe the fucking apple beyond your opinion of it for anyone to understand it or base their own opinions on it, and thats what genres do.

Your views are based on a lack of understanding. It is unfortunate that you had to paint yourself as a moron to learn better, but it's for the best.