If you paid someone to study a million books and write a novel in the style of some other author you have not violated any law. The same is true if you hire an artist to copy another artist’s style. So why is it illegal if an AI does it? Why is it wrong?

I think this is intentionally missing the point.

LLMs don’t actually think, or produce original ideas. If the human artist produces a work that too closely resembles a copyrighted work, then they will be subject to those laws. LLMs are not capable of producing new works, by definition they are 100% derivative. But their methods in doing so intentionally obfuscate attribution and allow anyone to flood a space with works that require actual humans to identify the copyright violations.