Well, there's a difference between "fun" and "funny". Putting something into the Comedy Cafe practically puts a "this is funny"-tag on a thread, which automatically takes some of the "surprise" effect which makes things funny in the first place. Nonsense threads like the Latoya Jackson one live from acting like they were not supposed to be funny. Putting them into the Comedy Cafe would be counterproductive.
And Sword Association wasn't "funny", either, but fun. The difference is that there is no pre-programmed joke or anything anywhere, but you can feel free to mess around, as long as, in this case, it has anything to do with swords.