Obama let the top brass decide. They decided to let in some trans. Trump just overruled them, on Twitter.When Obama forced transgenders on the military there was huge opposition from the military.
The information is not that hard to find.
Kinda like Trump trying to overrule the management of the USPS. They find Amazon's business good for the Post Office. But Trump has another agenda. I think that it's pandering to his base.
Tom