Look up, what a collage is as an example how weird copyright is.
Creating a physical collage is not copyright infringement because no copying is involved, even at the “copying into memory” level. But the creator does not hold sole copyright over the result. You can’t use collage to wash off copyright. The creator doesn’t need copyright in order to display their work.
Collage on a computer, you might be able to get away with it by arguing fair use, depending on the jurisdiction and the lawyers involved. It helps that the collage artist is actually applying their own creativity, unlike an algorithm. But the biggest protection for collage artists is that most copyright holders don’t care enough to go after them. Even if the copyright holder finds out about the collage (a big if), suing is expensive, it’s bad PR, and there’s little to gain by suing the average collage artist. Automated copyright enforcement algorithms like on YouTube absolutely will go after collages.
But my primary argument isn’t about what the law currently is, which varies a lot by jurisdiction and is generally outside of my area of expertise. My argument is about what is morally right, and what the law should be.