alot of it is simply because the FDA is lazy and doesn't care about niche meds. other part is known side effects, interactions with surgery and liver health especially.
QuoteWe have observed that patients who undergo an operation exceeding three hours tend to have more bleeding and the INR is reduced–possibly due to prior antiandrogenic medication with the antiandrogen cyproteroneacetate–so that such a prophylactic measure is not necessary and might introduce a risk intraoperatively.
ninja edit: most of the antiandrogen effects are, IMHO, 80% psychological as some T is needed to keep SHGB in line and things happy, but not enough T for effects (morning erections). if that makes sense