Notice how pretty much none of these are added in the last 10 years?
Android's become 'more mature' - ie. Boring, and the joke to code ratio is dropping rapidly.
If you're 10 hours into debugging something, or you're swamped with a horde of bug reports and bad reviews, and after digging in you find the bug is in upstream code laced with humor, it comes off as if upstream isn't serious about software development or is making light of the responsibility. Lots of things start small, but X11, Android, etc etc are now used by millions, in lots of different situations, and humor is highly contextual.
Good, I hate ‘funny’ code. Just get to the point, I’m not here for someone’s notionally hilarious inside joke from 18 years ago.
I've noticed that modern life is in general less fun than it was 10 years ago. It might be me getting older, but I'm sure there are bigger societal changes too. BTW I used to browse tcrf.net and it was so interesting that video game developers would leave pieces of themselves in their work. Love letters, old memes, angry letters, random shit, whatever. Meanwhile modern programming is all about pRoFeSsIoAnALisM and MaXiMiZiNg PrOdUcTiViTy at all costs.