I'd bet that most readers of this blog are hesitant about music genres. Me, I like them to an extent: it helps to narrow music for the purpose of superficial discussions, and can help to find music in a store (brick and mortar or virtual). I don't like them because of the same reason given above: they narrow music. Like Duke Ellington said, "There are two kinds of music: the good kind, and the other kind." It would be nice to live in a world without labels, but that's not realistic (in music, in the greater culture and society, anywhere).
I just started reading a book that has some good words on this. How the Beatles Destroyed Rock 'n' Roll by Elijah Wald is, even only 30 pages in, a great read. I'm sure I'll write more about it as I get further in. I wanted to share this small bit. I like his analogy about musical genres, comparing them to speech and language.
... All genre divisions are arbitrary ... Music is like speech: The way people talk varies from neighborhood to neighborhood, year to year, and region to region, and decisions about how to divide all those ways of talking into languages tend to have more to do with politics and historical hindsight than with linguistics. The fact that Dutch and Flemish are typically classified as two different languages, while the varieties of Arabic spoken in Egypt and Morocco are typically classified as dialects of a single language makes no sense in linguistic terms, but it reflects the historical reality that the Dutch and Flemish have preferred to accentuate their differences while the Moroccans and Egyptians have preferred to stress pan-Arabic unity. Similarly, there is no overriding musicological reason why Scott Joplin and Fats Waller should be placed in different categories - ragtime and jazz - while Waller and Chick Corea are both considered jazz musicians. The reason most historians agree that ragtime was supplanted by jazz in the late 'teens but that jazz continues to evolve in the twenty-first century is that in the first instance the balance of critics chose to signal a split while in the second they chose to emphasize continuity.
Wald, Elijah. (2009) How the Beatles Destroyed Rock 'n' Roll. Oxford University Press: New York. (27-28)