The difference is that the llm has the ability to consume and remember all available information whereas a human would have difficulty remembering everything in detail. We still see humans unintentionally remaking things they’ve heard before. Comedians have unintentionally stolen jokes they’ve heard. Every songwriter has unintentionally “discovered” a catchy tune which is actually someone else’s. We have fanfiction and parody. Most people’s personalities are just an amalgamation of everyone and everything they’ve ever seen, not unlike an llm themselves.
I think we need to re-examine what copyright should be. There’s nothing inherently immoral about “piracy” when the original creator gets almost nothing for their work after the initial release.