The difference is that AI models so closely recapitulate specific features in copyrighted images that stock image company watermarks show through [0]. This is several levels beyond a human artist implicitly getting inspiration from copyrighted images, and more on the level of that artist explicitly copy/pasting specific pixels from them.
That's exactly my point — they replicate highly specific features in images with such fidelity that their training is not analogous to humans' artistic inspiration.
They replicate common features. If you paint the same happy little tree in your picture as thousands of other people then it will probably show up in an image produced by a model trained on those images but your tree is hardly unique then isn't it?
How is the ai supposed to know these watermarks aren't a style element? They're present in tens of thousands of input images, after all. Therefore, I'd say this is a bad example of an AI literally copying from one specific source. It's similar to it using Arial letters: they're everywhere in the source data.
The i stands for imagination/ignorance at the moment. Intelligence (or something indistinguishable from it) doesn't seem too far away but isn't here yet.
So all we have is a dumb bot that can appropriate styles and ideas. Revolutionary, but not quite to the extent needed to sue it for copyright.
[0] https://hackernews.hn/item?id=32573523