I appreciate the fact that, apparently, the DoD is treating this migration just like morning exercise. Plan ? Just go out and run, numbskull. Oh, it's harder than it looks ? Maybe we should follow the recommendations ? Nah. Just put on another pair of shoes and it'll sort itself out, probably.
These "security concerns" of theirs, they do not prevent planning. There's no reason to not plan properly because of them. Lack of personnel trained in IPv6 ? So plan to train personnel. Email not compatible with IPv6 ? Plan to replace it, or upgrade it.
Planning is not doing, but if you don't want to plan, you won't be doing for sure.
And the DoD quite obviously does not want to plan. Probably because really doing so will put a lot of ugly figures on an official report, and the DoD doesn't want to show those figures.