> is what style guides that go into the minutiae of comma placement try do do
Eh. There might be a tacit presumption here that correctness isn't real, or that style cannot be better or worse. I would reject this notion. After all, what if something is uniquely crap?
The basic, most general purpose of writing is to communicate. Various kinds of writing have varying particular purposes. The style must be appropriate to the end in question so that it can serve the purpose of the text with respect to the particular audience.
Now, we may have disagreements about what constitutes good style for a particular purpose and for a particular audience. This will be a source of variation. And naturally, there can be stylistic differences between two pieces of writing that do not impact the clarity and success with which a piece of writing does its job.
People will have varying tastes when it comes to style, and part of that will be determined by what they're used to, what they expect, a desire for novelty, a desire for clarity and adequacy, affirmation of their own intuitions, and so on. We shouldn't obfuscate and sweep the causes of varying tastes under the rug of obfuscation, however.
In the case of AI-generated text, the uncanny, je ne said quoi character that makes it irritating to read seems to be that it has the quality of something produced by a zombie. The grammatical structure is obviously there, but at a pragmatic level, it lacks a certain cohesion, procession, and relevance that reads like something someone on amphetamines or The View might say. It's all surface.