As other people have explained better than I'm about to, Satanism isn't worship of the devil, it's basically egoism with ritual. Most real-world satanists don't listen to black metal, nor do most black metal musicians consider themselves satanists. Early black metal bands were involved in burning churches as a protest and wanted a return to the culture and traditions of Scandinavia, but since Satyricon and Cradle of Filth got major label contracts in the late '90s those sentiments have basically been extinguished in the name of making money.
As for the old farts complaining that you can't make out the lyrics clearly - your older relatives probably had the same complaint about Elvis.
As for the old farts complaining that you can't make out the lyrics clearly - your older relatives probably had the same complaint about Elvis.



