This behavior is actually specific to ChatGPT because they lost a music copyright lawsuit in Germany. They would refuse to output music lyrics too but they would happily do analysis on lyrics if you supply them. I suspect there might be a guardrail model involved here.
The trouble is, even if they refuse to output that copyrighted material, they were still trained on it without proper licensing and will still produce derivative work based on them because that's how this whole thing works.
So at the end of it, if we win enough lawsuits to demarcate some knowledge out of bounds, sufficient enough to make a difference, I wonder how that will affect the AI. Make it dumber because it does not have that data, it make it smarter since it will need to reason better with smaller knowledge base.
Claude does this too. I asked it recently to compare two versions of a song (the original and '97 remake of EPMD's "You Gots To Chill", if anybody wants to try and replicate this) and it flatly refused. No amount of reasoning would knock it off of its moralizing perch - reproducing any part of lyrics is expressly prohibited.
In light of this and other ridiculous behavior I'm migrating to my own OpenWebUI instance with open-weight models from OpenRouter (with ZDR, of course). We'll see how it goes.