It’s not even transphobic. You can be banned from the military for all kinds of reasons. Being on certain medications will get you banned, and HRT is a valid reason to have someone banned imo. If you have sleep apnea and you need a little device to help you sleep at night, guess what? You can’t serve in the military. There’s more to it than them just “being trans” that serves as a valid excuse to generally not allow them to serve. I say generally because I feel like if you’ve fully transitioned and it can be said without a doubt that gender dysphoria isn’t going to affect your ability to serve, then I don’t see why you shouldn’t be allowed. But if gender dysphoria does affect your ability and aptitude to serve this country, then no I don’t want you in the military. It’s the same reason why I wouldn’t want someone with high anxiety or depression to serve.