Good writers are often good in recognizably unique ways. To the extent that LLMs produce “good writing,” which I happen to think they mostly do, they tend to overuse specific devices which give their writing a quality that most people are already sick of.

You can tell good writers from LLMs because good writers post comments that mean something, that add to the conversation, that bring in personal experiences. While LLM comments just summarize the article and end with some engagement call to action like "Curious to hear what others think"