> Seems more of a subversion of joke structures than a lack of understanding.
Yeah it can be unintentionally funny in that way but children definitely aren't trying to do that. They just don't understand how jokes work.
Seems like you stumbled over the concept of the Antiwitz. Congratulations :D
The concept exists in English as well. Kaufman, Norm Macdonald, Isaac Asimov.
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> A man goes to a doctor's office and says "Doctor, I'm a chicken." And the doctor says "No you're not."
> There are two guys, riding a bike. One is washing his hair. And the other one is not.
> What do you get when you cross a t-rex and a chicken? Nothing but death.