I'm with you a little bit, Harry,in that I think that we should just enjoy the music without worrying too much about what it is called.
However, for a shop or a library you probably have to call it something!
My own system is to file it all alphabetically, Jazz (ancient & modern), folk, C & W, classical, all together. I can always find anything I want, and choose according to my mood.
If I bought it, it was because I enjoyed it, if I don't, I don't buy it.

FC