I respectfully disagree that these kinds of questions should be dismissed out of hand. I would rather say, "sometimes yes, sometimes no."
In my mind if the ordinance in question is able to control it's decent using traditional principles of aviation (movable wing surfaces, etc), then it would be okay to ask that kind of question provided the question is about the flight of the ordinance itself. Eg., "How does a Tomahawk cruise missile fly so far with such small wings?" Or, "Why do some air to surface missiles use scram jets and other's use fan jets?"
But, I would agree with Kevin that we want to stay away from questions about the tactical/strategic function of the ordinance, it's damage capabilities or it's guidance system. Eg., "How much force is generated by a 500lbs bomb?" Or, "Why would one use a depleted uranium tip instead of a steel or aluminum one?" Neither of those questions are within scope, they belong on a military stack (if only one existed...please support this proposal).
So, like I said, sometimes yes but sometimes (heck, the majority of the time) no.