the full on em dash requires a different character than - or --
it was generated that way, or else this person happens to know the correct combination of buttons to make that happen.
in 2026, at least 20-40% of social media traffic is bots (and probably higher with better LLMs), so it is usually safer to just assume.
On a Mac, at least, the "correct combination of buttons" is trivial and easy to remember, even for someone like me who rarely uses em-dash. (But, I want to start using it more because I'm sick to death of people treating it as a scarlet letter.)
Option-shift-hyphen
Thanks for sticking up for my humanity ;)