What you say is not in conflict with AI-generated content being white noise. Even if you find some piece of AI-generated content useful, it is still white noise

What you say is not in conflict with AI-generated content being white noise. Even if you find some piece of AI-generated content useful, it is still white noise if it is merely combining pieces of information found in its dataset and the result is posted online or published elsewhere. There is no signal being added in that process, and it pollutes the space of content. Humans are also prone to doing this, but with the help of AI, it becomes a much larger issue. "Signal" would mean new data, which is by definition not possible via LLMs trained on publicly available content, since that means the data is already out there, or new and meaningful ideas or innovations beyond just combining existing material. I have not seen LLMs accomplish the latter. I consider it at least possible that they are capable of such a feat, but even then the relevant question would be how often they produce such things compared to just rearranging existing content. Is the proportion high enough that unleashing floods of AI-generated content everywhere would not lower the signal-to-noise ratio from the pre-AI situation?