Quite frankly, from the standpoint of an employer who oversees a male-dominated environment...it's a good practice in concept, but a bad one in implementation (I don't think anyone should be fired or held from promotion because of it). It should be a "rule" of common sense: keep quiet and you won't upset the apple cart.

Why?

The majority of people aren't as PC or as accepting as one would believe. Most - and I do mean most - people are uncomfortable with gays. You put a openly gay man in a factory and it creates conflict...whether it's rumors, harassment by his straight peers, or people not wanting to work with him. I've had to deal with many such conflicts over the years.

It's a powderkeg just waiting to explode. That being said, keep it to yourself. Doing otherwise...and announcing one's tendencies....begs for trouble. That's just the way it is, especially in a male-dominated environment...be it a blue-collar factory or the military.