Why would they have to? Just to avoid being accused of using a slop machine? If that is the only criticism you have against LLM produced text, then there is no problem.

And I'm saying this as somebody who is strongly against LLM-generated content of this form.

I have no problem with AI-generated text.

But I do have somewhat of a problem with unedited text. Personally, I even take the time to edit my HN comments.

And, for the same reason I'd have a problem watching the same episode of the same show every day, I have a problem with reading text that feels like a super derivative clone of tons of other writing. Which is usually what you get when you don't edit your AI-generated text.