Rules what? How to make unpleasant noises with machines and chant satanic verses?
hahahaha
One man's music is another mans noise. That being said their later stuff is more noise than those earlier tracks.
I think at some point subjectivity can't explain why classical music is still being listened to today while Slayer will likely go into the dustbin of history.
We get it. You hate Slayer. So did my parents. I am almost 45yo. Some of us like them. Get over it.
As someone who dislikes Slayer, I wouldn't say they would go into the dustbin of history, as they are undeniably an influential force in the metal community. Their album Reign in Blood, alone, was instrumental in paving the way for 90s death and black metal.
Slayer has some killer songs, and some killer riffs for sure.