In social media comments they came across as pompous even before LLMs and werent particularly appropriate for casual comments.
Though to be fair some people enjoy coming across as pompous and embrace the 'better than the peasants and their lowly minus sign use' attitude. Makes them feel special or as if their writing is markedly better than those without fancy punctuation. (It isnt).
Also yes, im describing two writers i know that are adamant about the em dash being 'a sign of an intellectual wtiter'...they are insufferable pricks.