Arguments saying that gender therapy is costly to the military isn’t valid. The cost (money, recovery time, etc.) of reassignment (hormones, sex surgery, doctors, etc.) is not different from the cost of treating other medical conditions (knee surgery, high cholesterol levels, etc.). The point to note here is that Gender Dysphoria must be recognized as a medical condition instead of a “choice” or “something controllable”. The cost of recovery is much smaller than discharging a personnel and retraining another from scratch.
Arguments saying that they disrupt military cohesion follows the same logic of discriminating blacks and LGB people from the military in the past and thus can be completely disregarded. 70% of people on age 17-24 in US do not meet military eligibility requirements, and many of those who do simply aren’t willing to serve. Trans people who meet the eligibility requirements are crucial to fill this lack with numbers.