Because if the comment is correct, it's useful signal for other potential readers to know that they can skip it.

I try to be as charitable as possible when reading and commenting online, but we don't have infinite attention and thanks to AI, it's easier than ever to end up wasting it on things that aren't worth reading.

(I'm not claiming that the article here is or is not an example of that.)

Even if it's not from an LLM, it's still wrong! You've focused on the last important of that comment, really.