That's really the curse of comedy. The whole point of comedy is to be subversive, to sneak in under the radar of "good taste" and "propriety." But it's hard to do that, a lot of the time it gets rejected out of hand, and it seems very inconsistent.
Comedy is subversive, but the venue is usually not. When a comedian gives a routine on stage, the audience is primed and has certain expectations. When the audience's expectations are not aligned, it is bad for both the comedian and the audience.
My limited experiences on HN as a junior user have yielded a certain kind of fuzziness as to what is acceptable. On any given day, there is a lot of variance in the content, but usually HNish and that's a good thing. Officially, the guidelines are posted and they have an emphasis on intellectual stuff/tone, but leave evocative content unexplained. So the community decides, which is usually sporadic, hap-hazard, heavily-dependent on who posted the submission (people have expectations about what Zed Shaw is going to say), and the touchiness of the content. This probably doesn't happen in other communities that are more clearly guided as either relaxed or strict.
I think that's a good thing. It keeps people on their toes, rather than trotting out the same stupid jokes time and time again. I'll vote for something that's funny in a unique way, but downvote anything smacking of a stupid meme that's been done to death.
It is true that you are given more slack when your name is known. Think of it as a corollary to the Picasso rule -- others have to know that you know the rules before you are given more leeway on how to break them.
The bottom line is that humour is easy to upvote, and in-jokes are easy to accumulate in any online community, and so we must be ever vigilant. There's nothing wrong with humour now and again, but it requires ongoing, active rejection, and yes, a bit of hypocrisy to avoid becoming Reddit, where every single story has a contentless pun-filled thread 20 levels deep with a reputation of 1000 at the top falling off logarithmically.