If you think HN is less fake than Facebook as far as personas goes that is probably more about your Facebook feed - HN is more homogeneous, certainly, but you don't become cultured because you've build a country club and everyone puts on a fancy accents inside.
On a side note, HN is the place person matters more than anywhere I can think of except for YouTube. Is it possible you feel like that because it's closer to your person/ingroup?