In addition, HN doesn't get much of the "classic" troll crowd (no matter if 4chan/8chan/outright real Nazis/gamergate) or Trump supporters - from the occasional politics thread aside, there's nothing much of interest for them here, and so the biggest blocks of trolls simply stay away.
The moderators here are very good at doing work upfront to save themselves work later, by making the site infertile ground for troublemakers.
The latest HN comment dump I could find with a quick search was from May 2018 [1].
There were 237,646 comments in total that month, made by 36,358 unique users. 75% of users posted 5 or fewer comments, with a median of 2. The most prolific user wrote 798 comments, dang managed 6th place with 425 comments.
Even if the numbers doubled since then, there is no need to moderate millions of users, as only (well) tens of thousands of them are actively participating.
[1] https://www.reddit.com/r/datasets/comments/6v685o/complete_h...
this is why.
"If you voted for Trump, you're at best a troll but most likely a Nazi"