I only did a quick skim of the article, so it's possible I missed it or am unfamiliar with this specific AI, but we don't even get to see the prompt or how he went about having the AI create this piece. It's completely possible that he does have reasoning for how it turned out and ideas on what the components of the piece mean to him. Just because the AI realized his piece rather than a paintbrush doesn't make him less of an artist.

If it's just a mishmash of different pieces put out without any meaning then obviously it's a lot less of an art piece and more of "hey it'd be cool to mix all this together"