I think it has more to do with maturity in music. Not even musicianship.
For example....
Funeral's-From These Wounds album. It was mature, it was heartfelt, etc. The average black metal album isn't intended to make you think, it's intended to make you "rock out" and headbang. Notice I said average. Something like... <code>, that would be different. I can't listen to any Enslaved before Maudraum, Beyond The Within because it's just stupid. It's barely even music.
Same reason I hate tech death. There really comes a point where you've been so desensitized by metal that you overlook genres that have no musical qualities whatsoever.
Just my opinion.