Why do you keep asking for medical specifics from me? If I give you an answer will you believe me? And if not , then why don't you go look it up? This is not some totally unknown things, people have been undergoing testosterone therapy for a long time. I'm sure you could find out, if you actually cared.

But since you asked, here is your answer-

HRT doses of testosterone are much lower than the typical doses taken by steroid-using athletes, and create testosterone levels comparable to those of most cisgender men. These levels of testosterone have not been proven to cause more aggression than comparable levels of estrogen. It is assumed that the effect of the start of physical treatment is such a relief, and decreases pre-existing aggression so much, that the overall level of aggression actually decreases.