You're assuming some data hasn't been delicately fudged in order to anonymize the source. Maybe he worked there between August 2016 and September 2017. Maybe is a Navy, not AF veteran. Maybe he isn't a he at all. Who knows?
I don't find that the military information was valuable, it could've easily been left out, and the veteran question the author posed could have still been asked if it were rephrased.
There are trade offs in all of these methods, but I don't see them as being particularly wrong if you want to provide color to your story without materially affecting it, and can be confident that you aren't helping to identify your source.
If it is just a coincidence that the details of your fudging match a specific person, then they can still deny it. I don't know, but the point of all this is to protect a source, not to protect a random person who might be implicated by bad luck and punished illegally by bad actors.