The most telling point here is the complete failure of the "oh no, we can't trust them in the showers" brigade to actually come up with any evidence - whereas the facts speak for themselves: there have always been homosexuals serving in the military, and it has never been a problem in itself. The only difficulties have been caused by the ignorance and bigotry of others.
Meanwhile, a hypothetical question. Should Alan Turing (
http://en.wikipedia.org/wiki/Alan_Turing) have been trusted with military secrets? After all, he was as gay as they come (or at least, as gay as he could get away with, and a little
too gay for his own good eventually), and was working at Bletchley Park (
http://en.wikipedia.org/wiki/Bletchley_Park). What a risk to security!