Ahh, the joke is that there is an event in Germany called "fisch sucht fahrrad" (short FSF) which is a big gathering of singles to find potential partners. A bit like Tinder, but before online dating was invented.
A gathering of FSF (free software foundation) People also consists of mostly single men.
i'm 22 so i wouldn't call myself a kid, but it depends on the point of view I guess