As long as Gays do not "show off" their lifestyle in the military camp or base, I really don't see a problem with them being in the military in general. They have just as much of a right to defend their country as the typical "straight person". Just keep it to yourself.
I feel that it is an appropriate rule given the people that normally are troops in the army. A lot of the people in our armed forces are narrow minded and very aggressive. I believe that the rule protects our gay troops and tries to allow them to have a normal life like any other soldier.