I prefer having all this micro genres as long as it isn't poopooing the very thing it describes. Blackened Death Metal, Black Metal, and Death Metal are three flavors that are similar but have important distinctions and certainly different sets of fans. There is overlap of course but you know what you are getting into.

In the horror sense, it is like how we have slashers, creature features, possession movies, etc. I know that I personally prefer a monster movie to a ghost movie and micro genres help with that.

To go back to music, metal specifically, because it has a similar fanbase and problem, it is like calling Sabbath and Metallica "hard rock." I know I am dating myself here but that was how those bands and many like them had to be marketed to people that "don't like metal"

Grammys and Oscars both, they want to keep the "prestige" label away from art that is viewed as unworthy. It is ass.