The endocrine system is complex and involves multiple pathways and feedback loops. A single compound's weak or strong binding affinity to a receptor doesn't provide a complete picture of its physiological impact.
Receptor saturation (in this case, E1 vs E2; first pass metabolism turns E2 into E1) is something I had to learn out of neccessity because my endocrinologist didn't really do anything beyond loosely following ancient standards of practice (we don't have specialized gender clinics in Germany).