This is just as rehash of the debate around authorship for prompting a single image. If you had typed the same prompt on Google and picked a picture, or hired an artist with that prompt, you wouldn't claim to be the artist. Therefore you're having a different role than that in the process, ML model or not: publisher, producer, whatever.

The sooner these people come to terms with it, the better, so they can promote themselves for the skills they actually have (lackluster as I find them) and leave actual authors to carve their own niches among the incoming flood of generated content.