Moderation is necessarily inconsistent because we don't see everything that gets posted—there's far too much to read it all. We don't even see 10%; we're lucky if we see 1%. If you see a post that ought to have been moderated but hasn't been, the likeliest explanation is that we didn't see it. You can help by flagging it or emailing us at hn@ycombinator.com.

That said, if you're participating here, we need you (like other users) to follow the rules regardless of what other commenters are doing. It always feels like the other person (a) started it, and (b) did worse. Since everyone feels that way, using that as a guide for one's own behavior just leads to a downward spiral.