The Association was being a tad humorless there, and now they are paying for it. First off, the RCO is not a combat unit. They are a procurement office. They are the go-to guys when you need a $700 toilet seat real fast. The motto was "an inside joke," according to this news item, a subtle acknowledgement that there is no divine agency involved in overpaying for military hardware. This did not stop the atheists from bitching about it until the motto was changed, even though "miracles" aren't that far removed from "God" as a scientifically suspect concept.
This reporter himself, although a committed rationalist, often invokes the will of God in a sardonic manner, in particular when someone else is occupying the single bathroom in his condo when he needs to use it. "God wants me to take a fece right now," is what he says, when knocking impatiently on the door, even though he does not really believe in his heart that if there is a God the Almighty Creator, He would take an interest in the author's personal peristalsis.
Now the atheists have attracted the attention of the Congressional Prayer Caucus, a body that can match any other force on earth, including geological ones, for humorlessness. The CPC wants the motto changed back, apparently because they feel that once you start joking about God, it is sacrilegious to start joking about something else, and also in spite of the fact that maybe one percent of the hyper-religious yick-a-doos to whom they prostitute themselves for votes know that "Dei" is Latin for "God" in the first place. No matter to these prayerful public servants. If a dyslexic graffiti artist sprayed-painted "God" instead of "Dog" on the Washington Monument, they would probably introduce a bill to protect the defacement.
As far as this writer knows, it is still legal for actual combat servicemen to put depictions of God, Thor, Anubis, Shiva, Satan and other mythical scourges on their weapons as messages for those they intend to obliterate with them. Click here for an illustration of a lesser god on an older warplane. And if a rationalist combat unit in today's Air Force wanted to sloganize the warhead on its Predator drone, something like "LOOK INSIDE FOR 72 VIRGINS" would be good.
Hopefully, they wouldn't have to explain to their fellow freethinkers that they were just kidding.