I am so much man that I have to crossdress to provide some balance to the force. Kidding
Seriously though, I couldn't have said the above any better. As to WHY gender is a spectrum and is not tied into sex, well that's a question that's a bit beyond my pay grade. If psychologists and researchers can't figure it out then I doubt anyone of us has a sufficient answer. Why let this worry you? We haven't got a theory unifying gravity and quantum, but we still use relativistic and Newtonian theories to keep satellites in orbit. Let's just roll with what we DO know, which is that we LIKE crossdressing. That's good enough for me.