Firstly, I don't understand your connexion between gays openly serving in the military and the destruction of the United States Armed Forces entirely -- I hope you'd made a typographical error. If not, and you believe that gays openly serving in the military will destroy the military as we know it, then you're too far gone.
As well, to answer your questions, yes. Gays can openly serve in all of the major, and most of the minor nations on Earth. The simple fact is that, for whatever reason, be it extremist religious tendencies in the States, or just plain conservative resistance to change, the States seem to be one of the few nation that cares one way or the other whether a person is gay or not.
Among the other big-name nations that don't allow gays to openly serve? Iran, Egypt, Lebanon, Syria, Jordan, Saudi Arabia... Some fine bedmates there, mate.
