Not just the em dash, the whole post stinks of ChatGPT, and there are two other obvious tells in the sentence I quoted.
If you know you know.
Fair enough. I'm sensitive about the em dash being used as a tell, which I've seen mentioned once or twice, because I don't want people to dumb down punctuation to avoid being confused for an LLM. I'd guess it's a temporary issue until the LLMs get so good at blending in that we can't tell anymore.