Why do we classify music?

Why do we classify music?

Music today is a less defined culture compared to that of the 20th century. Nowadays we have genres and sub genres up to our ears just to put a label on something that should be simple. I am as guilty of this as anyone, but when did we start saying "oh yeah...I like [insert generic genre here]"
It's unnecessary, and almost certainly detracts from the overall concept of music. Nothing needs to be branded into categories upon categories until an artist's songs can have different genres within an album or even within a song. There is no need to call the guitar solo after the middle eight a "hard-core metal riff" and then revert to labelling the rest of the song as "indie." This divides people immensely on what should be an experience enjoyed by all. Nobody is completely devoted to one genre of music, and no metal-head can say they don't enjoy the occasional "gay-pop song" once in awhile. It shouldn't be that someone can't enjoy a certain artist just because they have shown their allegiance to another. I'm, not saying that this is common practise today, but we have certainly gone to far in deciding what music is this, what music is that. If you enjoy a certain type of music, listen to it, but don't let it stop you listening to another.