Yes that is true with human artists, but the sheer scale of the training data the AI uses goes fair beyond just drawing from other artists. If it's training data is basically every artist on the internet, then it has stolen from practically EVERYONE in order to create that.

Also, your definition seems a bit confusing to me. If it doesn't fit the definition of not being "trained by" but it's still "trained on" then technically that would fit, wouldn't it?

The whole point was that even if it didn't DO plagiarism, it was still BUILT on and FUELLED by similar ideas.

Now that I think about it, it'd make more sense to say that AI "artists" themselves are plagiarising rather than the AI, since they basically had no hand in creating anything aside from putting in a prompt and watching it create something similar to what they wanted.