So, on the one hand, Microsoft claims their software has flaws so deeply rooted that revealing them could endanger national security.

And on the other hand, they've been lobbying for use of their software by...

... the Department of Defense.

Well, at least the DOD has some experience dealing with the flaws in Microsoft software. A few years ago, a "smart ship" in which just about everything was run by Windows NT had to be towed into port after the propulsion system bluescreened.