The OP topic isn't about differences in sexual ID or attraction. Such have existed since our species arose.
Militaries must determine what factors eliminate a man or woman from active service. All service personnel are (ideally) put where they fit in best. The entire machine, from recruiting through logistics to combat is intended to function as leanly (inexpensively, in money and resources) as possible, with the greatest alacrity in destroying the enemy's capability to wage combat.
Today we have an unprecedented movement toward liberal (progressive) thought, carried out by activists. Their motives are genuinely altruistic. That doesn't make them right much less wise.
Lessons from the past are largely ignored, brushed away, with assertions such as, "That was then, this is now; things have changed." So they absolutely do not believe the adage of the ages, "Those who do not learn from history will be doomed to repeat it."
Militaries that have inculcated "progressive" elements have failed. One of the most basic and also the worst is the mercenary reliance: the society becomes so unwarlike, or unwilling, that they place their security in the hands of foreign fighters.
Believe it or not, that is the direction that our current path is taking us. This one tiny reversal of the POTUS's of that trend will amount to nothing if it is not followed up by a sweeping reformation, from the top down. Expenditures far more damaging than anything so far spent on transgenders need to either be cut out or cut down. Entire bureaucracies that have been built up to "minister" to special interests in the military need to be abolished as inimical to efficiency, both economic and combative.
Should the President answer to the advice of his best informed, most wise generals and their counselors, we shall see such a change in the US military structure that will be truly historical.
So don't get all caught up (distracted) by a relatively puny side issue bothering society that is nothing but an argument about sex.
The military cannot afford to address any issues about sex beyond the punitive. Soldiers must allow their training to turn off the sexual side when drilling and going forward to battle. The punitive is there to eliminate the constant threat of breaking ranks to engage in rapine and its attendant enticements. The soldiers are not sexual beings to the military. If they become such, then punitive measures will put them back in line or get rid of them.