I think many who buy into "He/she is military or LE," are typically beginners. Fundamentals, which are *generally* taught pretty well are pretty basic and what I think many of the beginners seek from people they believe are experts. That in itself shouldn't be much of an issue. I think the big problem stems from the fact that the attitude instilled into the military (can't speak for LE), is to be so confident in your answer even when you don't know it or know you're wrong. People in the military and I am assuming LE do not want to feel inadequate in an area where many have high expectations.The other problem is one that stems out beyond firearms and one of which I encounter fairly regularly being former military. People, especially of the young adult age group, really want to live their fantasy through the militarys reality. What I mean by this is often times someone will ask a member of the military a question, and they may not have the answer. A typical response is "Awww come on man, you were this/that/the other!....but like I thought all Marines see combat and are rifleman...etc. etc." Some folks will just let them hear want they want to hear. I don't however think this is acceptable in talking about firearms and shooting.
Everyone else pretty much has said what needed to be said