I think it's related with the "substantive elaboration" test with regards to copyright (sorry I can't remember the proper term). If I just copy a scene from your movie, you can probably sue me. If I take some elements from it, but do my own thing so that it read more like a parody/comment / meta-comment, then it's ok.
Is AI just parroting back stuff or is it creating new things? A few years ago, I would have said it's just parroting. With the current models I think we are midway (it will depend on the propmt too!). In a couple of years my bet is that we'll be clearly on the "creating new thinfs territory".