I am very curious when seeing people make fun of other people's package when in reality it seems like it doesn't. Is this a joke than spans back into the books or is just a joke today?
Genital size is likely something that long predates recorded history. I suggest you ask this in /r/evolution or /r/askscience. Competing on the size of genitalia is found not simply across species, it is across phyla. As in birds and bees do it.