Nothing about those doses of hormones are harmless. If someone is transitioning, either they or their doctors considered it worth the risk - but the risks are serious.
People have already made up their minds and it's inherently politicized, so if the research is funded by Republicans then it will be a study designed to emphasize the risks and harms and if it's funded by Democrats the opposite. Which means it's a waste of money to study because the outcome is decided by the political inclinations of the party that initially funded it, whereas the purpose of actual research is to study a question whose answer isn't known from the outset.
These hormones have been studied, both for this use, and in the general population for other uses, for literally decades. At this point actually more like 50 years.
While i’m sure there would be some additional data/value from an additional study, it’s not like any of this stuff is new or novel in any way.
I’m not sure how or if that agrees with or contradicts your comment, or same with whatever political BS is going on, but this stuff is pretty well understood at this point.
Just like GMO, something like that alters our biology to such significant level, there ought to be some inter generational studies carried out before trying it on human.