Humor may be a part of life and discourse, but in certain cases, and especially on the internet, it distracts from the real issue at hand, as most slapstick fails to convey meaning. If you can make me laugh and then think, then more power and karma to you, but most of us are unable to produce such witty insight on the fly all the time. We try. We fail, and we spam. That's why HN doesn't like slapstick jokes. If one person starts using slapstick then it creates a chain reaction that distracts from the real issue at hand.
Such slapstick doesn't create meaning. It ends up destroying it.
I hope that made the issue clear to you.
There's a place for those chains of jokes, and that's mostly on Reddit (which I enjoy browsing often). But I would prefer to keep the discussion here on HN a bit more meaningful.
Reddit tends to be overrun with memes and jokes, and HN has always been more about lively discussion and facts. Reddit used to be like that a couple of years ago.
I like good jokes, but when I want some, I go to bash.org or the like ('Humour' folder in my GReader has more feeds than 'Technology'); but HN is not for jokes, it's for good discussion, so let's keep it like this.
There seem to be a lot more reposts and borderline-spammy self-promotion or poorly disguised press releases.
Memes, on the other hand, are repeated endlessly. Perhaps still funny, but it's the repetition that drives people away and dumbs down threads, because it contributes literally nothing, but it does distract. It also turns the place into an echo chamber - others were very likely thinking the same thing - and group-think is dangerous.
And people who choose to immigrate to a country may do so for a variety of reasons; I know a number of anglophones who hate living in Germany and are only here because of work.
As for myself I have a rather nasty looking ice-axe somewhere...