Its humor. Get over it.
EDIT: Actually this comes right out of military humor (yes there is such a thing). Its a response to idiots insulting a belief system that they do not engage in and love to ridicule.
Its like the airborne jokes:
You might be airborne if your most common cologne is bug juice.
You might be airborne if you plan how to kill everyone in the room if it turns out they are terrorists just for practice... except the weasle attorney over there... he will talk.
Or Air Force:
In Heaven everyone is a Captain except God. God is a Major.
In Heaven its always VFR and there are never ATC delays.
In Heaven the girls are all friendly and fighter pilots are allowed three.
In Heaven Beer is free but whiskey costs a nickle.
In Heaven there are no fat chicks and the ugly ones look like Sophia Loren.
Get it?
