> anyone saying that’s a sign of LLM use should not be listened to
You don't need to believe me. You can read the studies about its statistically higher occurrence in LLM writing vs human writing (https://arxiv.org/pdf/2603.27006) or you can do the analysis yourself.
Also, no one said you should stop using them. But overusing them, along with emulating some of the other common traits of LLM generated writing, will give people the impression that you didn't bother to write something yourself.
You’re misunderstanding the problem: LLMs using emdashes more than the average human still doesn’t tell you that the poster you’re interacting with now is an LLM and not one of the many humans who used emdashes before LLMs existed and are the reason why LLM training picked that up as a good trait. Humans shouldn’t stop writing well just because bots were trained to mimic them.
One other problem with this as a heuristic is technical: they used to be hard to enter on Windows so mostly only professionally-edited text there had em-dashes while the ease of entry on Mac, iOS, Android, and to a lesser extent Linux meant that they were more common there. I suspect that this list disproportionately lists Mac users:
https://www.gally.net/miscellaneous/hn-em-dash-user-leaderbo...