In folk music for example, performing someone else's work is not disparaged at all historically. It was common for most musicians to travel around and teach each other songs.
In pop music we see sampling has increasingly become a major part of the art, and only really controversial when someone tries to avoid paying the original artist their fair share (which is itself a topic of debate).
In the visual arts it's much different. There is of course the famous Picasso quote: 'Good artists copy, great artists steal.' But even in the tone of that quote you can tell there's a different cultural acceptance of reusing work.
Writing is tricky because referencing or quoting another author without attribution is a common feature of "high brow" works. T.S Eliot for example borrows heavily form past authors, often without attribution, but assuming an audience which knows enough to not require attribution. However at the other extreme you can get in trouble for plagiarizing your own work.
Personally I think Diffusion models and LLMs are just bringing up an issue in the visual and literary arts that was already forced to the attention of musical artists during the rise of early hiphop djs who showed that you can genuinely create something new nearly entirely by cut and pasting existing works.
One thing I would point out: It seems to me that copying/borrowing/reusing are equally present in all creative fields, they just are willing to admit it to different degrees.