Critique of the output is fine in my eyes. If you don't enjoy the style, format, choice of words, etc I think that's fair game even if it's superficial/subjective. It often is with art.

Placing a value judgement on someone for how the art was produced is gatekeeping. What if the person is disabled and uses an LLM for accessibility reasons as one does with so many other tools? I dunno, that seems problematic to me but I understand the aversion to the output.

For example maybe it's like criticising Hawking for not changing his monotone voice vs using the talker all together. Perhaps not the best analogy.

The author can still use LLMs to adjust the style according to criticism of the output if they so choose.