There's a flaw in the Milli Vanilli argument. The band had no input into their songs. They 'performed' them by lip-syncing on stage, but all of the music and lyrics were someone elses. Milli Vanilli had no part in the creative process.
That's not technically true of AI content. There's some tiny little seed of a creative starting point in the form of a prompt needed for AI. When someone makes something with Claude or Nano Banana it's based on their idea, with their prompt, and their taste selecting whether the output is an acceptable artefact of what they wanted to make. I don't think you can just disregard that. They might not have wielded the IDE or camera or whatever, and you might believe that prompting and selecting which output you like has no value, but you can't claim there's no input or creativity required from the author. There is.