It's not a shallow dismissal. Writing quality is core to the value of an article.
It's likely that but for LLMs, the article would not have been written. I'm glad it was written. It's also true that it's unpleasant to read LLM-written prose for those of us who have to read it all day for work.
Do you think your comment is a good critical comment that "teaches us something"? If not, it qualifies as a shallow dismissal according to these guidelines, even if it's not a shallow dismissal according some other definition or criteria.
I don't think it's shallow because writing quality isn't important, I think it's a shallow dismissal of the writing quality because it doesn't discuss anything interesting or substantive about the writing quality.
Also, what about the other guidelines? Comments should meet all of the guidelines, not just some of them. (I do get that some of these are borderline.)