johnr,
It is no secret that the military, in the name of national defence, is widely exempt from nearly all environmental regulations that the rest of us have to follow. This is non-news, and has been since around 1776. That doesn't mean the military can go willy-nilly contaminating the planet, but this is just one example of their not needing to follow the same rules as civilians.
I enjoy DEF about as much as everyone else that has to use it and I am still ok with the military getting special dispensation. As far as I know, government owned diesel powered vehicles for civilian agencies all have to use DEF. This is a topic specific to the U.S. military. Hence the similarly absurd reference to requiring our military to only use weapons available to the general public.