Because music is as messy as humans, and whatever we catalogue is arbitrary at best. See Every Noise: https://everynoise.com/ https://everynoise.com/ Is moder

Because music is as messy as humans, and whatever we catalogue is arbitrary at best. See Every Noise: https://everynoise.com/ https://everynoise.com/ Is modern chamber music different from modern classical, and why? How different are Polish free jass and free imporvisation? Canadian black metal and Norwegian black metal and Dutch black metal? To some, there's no difference. To others, there's a world of difference. Here's more on the difficulties: https://everynoise.com/EverynoiseIntro.pdf https://everynoise.com/EverynoiseIntro.pdf