So did every author of classic literature. People who think they can spot AI writing by simple stylistic indicators alone are fooling themselves and hurting real human authors

It's because LLMs were trained on classic literature that they began to use em-dashes in their now-famous manner.

Seriously, highbrow literature is heavily weighted in their training data. (But the rest is Reddit, etc.) This really explains a lot, I think.

Let’s just say when my coworkers started sending emails with tons of bold and bullet points when they had never done that before I felt pretty justified in assuming they used AI

Same, but 5 years ago. Now they're ruined for me lol.