: He's always been described as paying close attention to his personal
: appearance to set an example to his subordinates/trainees. It's not that
: someone would order him to shave the beard off, he's just the kind of guy
: who would do it anyway.

That doesn't exactly hint precisely towards a regulation orthodoxy. I think a lot of the military standards people have the best impression of is with the U.S. military where there's little room outside of the unconventional forces for what I can only imagine they'd regard as a "deviant" appearance. Most other militaries don't care if their people are sporting beards.

What I imagine when I think of how you regard Mendez is a little like the example below of an old-school, by-the-book veteran who religiously adheres to arbitrary, usually impractical, and often bullshit grooming standards. I just don't think you'd see that with most special warfare operators.

There's a fine line between making sure your people don't look like dumbasses...

... and then making your people have "fashionable" birth control.