In Britain, homosexuality remains a bar to serving in the military.
2. Military training is not an easy life, and there are expectations of sacrifice -- including sharing close living quarters with a lot of people who will not be of your race, religious or political persuasion, or geographic background or sexual practices. Once you get beyond the differences existing between members of the same outfit, once your train together and work together, you discover similarities and mutual common ground for trust and respect without having to change, compromise, or threaten anyone's personal principles. Lack of privacy actually accelerates the process.
3. One traditional reason for keeping homosexuals out of the military has been discarded in the USA when a study done for the Pentagon found that homosexuals were no more of a security risk (being susceptible to threat of blackmail), than other soldiers.
2. What the military understands is that AIDS is a blood-borne disease. In peacetime that is hardly a problem. But in a war, which is the only legitimate business of the military, blood is shed. Others come into contact with it, and the probability of that blood carrying the AIDS virus then becomes a cause for concern.
3. The concern is not so much that homosexuals are in the armed forces, but that if the ban was lifted they would openly display their homosexuality, possibly undermining the morale and discipline of fighting units.