A better question might be why do you not find it funny.
The following extracts may assist you with some introspection.
https://theconversation.com/getting-serious-about-funny-psychologists-see-humor-as-a-character-strength-61552To be in on the joke you need to be able to:
Mentally represent the set up of the joke.
Detect an incongruity in its multiple interpretations.
Resolve the incongruity by inhibiting the literal, nonfunny interpretations and appreciating the meaning of the funny one.
There are at least two reasons that we sometimes don’t get the joke. First, the punchline must create a different mental representation that conflicts with the one set up by the joke; timing and laugh tracks help signal the listener that a different representation of the punchline is possible. Second, you must be able to inhibit the initial mental representation.
When jokes perpetuate a stereotype that we find offensive (as in ethnic, racist or sexist jokes), we may refuse to inhibit the offensive representation.
Violence in cartoons is another example; In Roadrunner cartoons, when an anvil hits the coyote, animal lovers may be unable to inhibit the animal cruelty meaning instead of focusing on the funny meaning of yet another inevitable failure.
Hope this helps
