Because a human understands and transforms the work. The machine runs statistical analysis and regurgitates a mix of what it was given. There’s no understanding or transformation, it’s just what is statistically the 3rd most correct word that comes next. Humans add to the work, LLMs don’t.
Machines do not learn. LLMs do not “know” anything. They make guesses based on their inputs. The reason they appear to be so right is the scale of data they’re trained on.
This is going to become a crazy copyright battle that will likely lead to the entirety of copyright law being rewritten.