Would it necessarily have more matches than a generic password dictionary? That would assume that military users are smart enough to not use the type of password they'd use on their personal email, but still stupid enough to use a dictionary word as a base.

He also didn't filter out non-military words. His 4,400 words would overlap considerably with list of common English words and could have been built by starting from any seed list.

I think it is an interesting concept. I can imagine this uncovering some jargon that is uncommon outside the niche, but unfortunately his experiments don't prove anything.