WWWTT:
My point was that if it was a racial group(black or otherwise) being banned, everybody would recognize that as blatant bigotry, and nobody would be on here defending the ban, even on the anti-militaristic grounds that you're using.
But it's easier to play your kind of games with the well-being trans people, since transphobia is still viewed(if just on a subconscious level) as somehow more respectable than racism.
And if you really believe that banning trans people from the military could in any way lead to the abolition or even just the weakening of the US military, well, I'm sorry, but that's just delusional. What it is far more likely to do is serve as a precedent for the banning of trans people from other goverment or non-governmental jobs. Which is one more very good reason to be against it.