It’s not a joke. Perhaps - arguably - in some context it might be. In this context it was not.
Jokes, like language, do not have absolute meaning. If they bend far enough, they break and cease to be jokes.
This “joke” did not have far too break. Simple gravity would seem to be enough to shatter this one. If it hasn’t imploded under its own weak gravity already, becoming a humorless collapsed quasi-stellar object, attracting other humorless objects in its wake.
