The rule was put in place because they figured out that is how it was spread, simple as that. As for the confusion on what the rule actually is, I think it is an excellent example of how DoD's IT infrastructure and practices are too Balkanized and dysfunctional. Then again, that may be a good thing. Clear as mud?
I got a couple of PMs after my last post. Folks, you misunderstand my post. It wasn't meant as a means to ask what's going on, it was meant as an observation on how much the policy has become rumor more than fact and how little people understand the overall system. One example was someone mentioning how "soon all the ports will be turned off." As was noted here, that's impractical since all the keyboards and mice are USB now.
That's all. Please don't report me to the local NCIS office, or worse, the local Mod squad, for soliciting information that doesn't need to be discussed in detail here.