Well, for the, ahem, people who can't see the humor... Trying to prove the Reimann Hypothesis is like trying to talk to God.

Now, it may be possible, but for those who have tried similar tasks - for instance, "Fermat's Last Theorem", often it has resulted in madness before success.

So, if you can see inside the joke, it is actually an allegory:

"A story, poem, or picture that can be interpreted to reveal a hidden meaning, typically a moral or political one."

The intention is to perhaps provide the following sentiment, "The very best of luck, but it might bite you in the ass"

As for whether humor is allowed, well I'm sorry but just as I believe that LGBT is acceptable, so is someone with who can make a few people laugh.