I really do see what you're saying, but have you ever heard of the term "Hard cases make bad law?" Your argument works well enough for trans identified females- a lot of them really do "pass" very well. But even after ffs, makeup, implants, etc, the majority of trans identified males do not. In fact, I would argue that passing is extremely rare. Even ones that do often only do so on camera. And I have to admit that trans women are right- "passing" is not a fair criteria. It's subjective. It would end up being a prettiness contest and most trans woman could never meet such standards. So the only fair, reasonable way to handle it is by biology. But keep in mind, laws entitling trans people to use whatever restroom they want weren't meant for those who pass. They could go into the bathrooms of the opposite sex with no problem. The new laws weren't meant for people who don't pass. Security guards are, essentially, not allowed to intervene when they see a man go into a women's locker room, changing room, shower room, bathroom, etc.

Women have been volunteered to take on physical risk so a few men can feel validated. That simply isn't right.