They must think as you get fatter it accumulates on the dick like it does in the fat sacs on their chests. I'm not sure what would be technically more horrifying for a man, gaining weight such that the pubic mound engulfs the penis,  or gaining in such a way you're left with some sort of growing permachub-on that leaves you with some sort of oversized jelly like 'nub'. In any event, blech.