The nature of the source, whether primary or secondary or tertiary, does not automatically imply anything about their biases. Even a primary research paper on a novel topic may be biased or wrong.

I agree that LLMs can't collect real world data and write about their findings. But that's true about most human sources too, isn't it? Except primary novel researchers or investigations or philosophies, what is original? Most human-written information is also secondary or lower.

The "best human sources" does not imply "ALL human sources."