That’s not true at all. Apple’s OS by default have smart punctuation enabled and convert -- (two hyphens) into — (“em-dash”; not an “en-dash”, which has a different purpose), " " (dumb quotes) into “ ” (smart quotes), and so forth.

Furthermore, on macOS there are simple key combinations (e.g. with ⌥) to make all sort of smart punctuation even if you don’t have the feature enabled by default, and on iOS you can long press on a key (such as the hyphen) to see alternates.

The majority of people may not use correct punctuation marks, but enough do that assuming a single character immediately means they used an LLM is just plain wrong. I have never used an LLM to write a blog post, internet comment, or anything of the sort, and I have used smart punctuation in all my writing for over a decade. Same with plenty of other HN commenters, journalists, writers, editors, and on and on. You don’t need to be a literal machine to care about correct character use.