I get the sense the point of the HN rule is to preserve unique human expression, regardless of how someone's communication skills are at a given point. Like, I periodically see articles on HN which have stale turns of phrase and signs of poor LLM use (which then becomes distracting while reading) and then the author sometimes mentioning in the HN comments they used an LLM to 'help' with their post based on some list of points they wanted to communicate. Yet when it's relied on too heavily like that it smothers the author's own voice.

If an opinion/idea is being communicated in the voice of another then something unique to that user has been lost. Like if I were to have a germ of an premise and told someone else about it and I found their thoughts clearer and how they expressed it and then copied how they'd expressed it then I think I'd be at least crediting them. Otherwise our own growth with self-editing and clarity will just atrophy and the internet will be a soup of homogenized ways of expressing things.