So... fuck 'em? Hit 'em with a: "You're absolutely right — em dashes are a common signifier of AI" and go about your business. Anyone creating on the internet[1] is running laps around the class of losers who run from post to post dropping useless comments.
[1]: I'd even go so far as to extend that "anyone" to: "anyone creating, even with AI assistance!"
[1]: I'd even go so far as to extend that "anyone" to: "anyone creating, even with AI assistance!"