What crap. First, remember that, in 1983, the year referenced in the OP above, the world was a much smaller place, internet access for the masses didn't exist and it was a lot easier to spoon feed people a bunch of crap like this, make it believable enough, present "evidence" and they'd buy into it. Think of all the TV specials from David Copperfield that aired back then (supposedly making the Statue of Liberty vanish or him flying through the air supposedly unaided by wires), highly publicized debunks that were done by The Amazing Randy, and shows like That's Incredible. Even stuff like pyramid schemes and chain letters were somewhat popular back then. Much of that almost seems novel by today's standards. Unfortunately there are still people who are ignorant and gullible enough to buy into this kinda stuff (as evidenced by certain Facebook memes that somehow go viral, etc.) but hopefully the masses have wised up and there's enough information on the web at one's fingertips that society as a whole is smarter and wiser than they were back then.
Regarding the subject of this thread, I remember in high school we were shown a video by one of our teachers who was a crazy bible thumper, and even as "kids" we knew the guy was out there. The video he showed made arguments about KISS and their makeup and antics and how they must be satanic, they took comments by one particular rock musician where he said some former, dead musician occupied and took over his body and soul when he was performing and tried to use that to frighten us away from his music, they took comments from John Denver who said "Thank you for allowing me to share Est with you through my music" to mean that Est (Erhard Seminars Training - look it up) was some type of cult that we needed to be wary of, and John Denver was poisoning our minds through messages in his music. They then showed us how the cola companies used subliminal messages hidden in movies shown at cinemas to sell product, and how easily we could be manipulated, and yes, they also aired an entire section about backmasking records. First, I doubt any serious musicians and bands would write lyrics and melodies specifically with the idea that if someone played them backwards at just the right speed, they'd speak a satanic message to them. Second, to me it was a very big stretch and a hard sell. Kind of like when someone tries to convince you that their dog has learned to talk and they tell you the phrase that the dog is saying and if you listen to its bark you can kind of maybe hear a little of what the owner has led you to believe is being said. Again even as kids this video we were shown had no effect on us and we all laughed it off, then went home and told our families and they had an even bigger laugh and head shake. Play that same video in schools now, and I'm sure a few parents would show up to speak with the school board.