There's no proof that they were involved in satanic or occult activity or psychedelic drugs. Christians write songs too. It doesn't mean they come from Satan.
Now it gets interesting with Black Sabbath. They claim that when they record songs in the studio each member got the song spontaneously as they were playing their part. That's obviously the work of Satan.
Wasn't saying they were involved with anything occultic or drug use, that's not a requirement to be a tool of satan..
Must of the videos of those song. You will see girls half naked, smoking and using of hard drugs. Is that what you want to see as Christian? Is that a positive influence on youth watching this videos.?