The answer is randomness. We don't come close to reading or even seeing all the posts here—there are far too many. Basically, it's the same boring reason as why cops don't pull over every speeder. Of course it always feels like you're the one being singled out when you do get cited (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...) - but this is an illusion, and so is the feeling that the mods are against you.

So when you see a post that ought to have been moderated but hasn't been, the likeliest explanation is that we didn't see it. And yes, you can definitely help by flagging it or emailing us at hn@ycombinator.com.

https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...