Categories serve a purpose to isolate stylistic differences in music. IE: I like Irish fiddling.
I hear definite regional differences and tend to gravitate to certain kinds which come from certain regions of Ireland. I am a bad fiddler (if you can even call it that) but I attempt to imitate that which I like. Donegal, for example, intrigues me.

I love the early recordings of Louis Armstrong and differentiate between the New Orleans style of jazz and the later Dixieland style which was probably popularized by the Original Dixieland Jass Band. Both have value and are different musical styles.

Visiting the Jazz Festival in Denmark, I was impressed by a European approach to jazz which was quite different than the American style they were seeming to emulate. No one would classify The Hot Club of France as an American jazz ensemble. Even Louis didn't apparently get it when he met Django. One of Louis Armstrong's fave bands was Guy Lombardo's Royal Canadians. Talk about different categories.

From a standpoint of isolating and recognizing certain styles of music, categories make sense. But from the standpoint of the creative musician, they may be impediments particularly if they are subject to pronouncements of music critics (Leonard Feather who claimed authority on jazz and dissed both Django and Jelly Roll Morton).

I think there has to be balance. Without these categories, though, the humor would be lost in Louis singing English madrigals or Alfred Deller doing chain-gang shouts.

Categories, however, don't mean you have to like everything in it. There is good and bad in all and this can be subjective depending on the listener.

Frank Hamilton