The military has a culture of its own, despite the fact most people only "visit" it briefly and a minority is there for their whole working life. When you adapt to that culture, your time there will be much easier and smoother. Apparently being anti-gay is a part of that culture in the USA. So, a person who never cared in his civilian life would suddenly turn anti-gay because it's a part of the business in the military.

Unfortunately such a culture will never change unless it's actively and publicly addressed. I have no doubt the troubles Ani predicted will happen to some extent but in the long run the development should be beneficial.