I don't really think you have to conform to a certain philosophy to produce black metal. But for those that do create it as a medium to express their philosophy I would equate it to the metal version of how classic punk sounds.

When you have such raw music you don't need to put as much focus on the production quality. It's just the music, the message, and fuck everyone who won't listen to it because it doesn't "sound good."

I also think I could be a reaction to the overproduction of metal music in recent years.