DoD should use NO commercial software. They should have their own research/development division which write secure software specific to and only available to the military.
That’s easy to say, but very costly to implement. Enormous training and communication costs are reduced by using standard software packages. MS Office, Adobe Acrobat, .jpg and AutoCAD have helped immensely as common formats in engineering circles.
At least we aren’t arguing over ASCII vs EBCDIC.