So which of those people have penises and which have vaginas? Should be simple enough for you to answer, right? How do you propose to police that? You going to set up a booth up front with a genitals inspector?if they have a vagina - female...if they have a penis - male...is that simple enough for you?
You're telling me if there was a video of this guy in line at a women's bathroom, you wouldn't say a peep if he says on that video that he has a vagina?
What if they're born with both; do they get to choose? And people born with neither; no washroom at all? And post bottom surgery, since you say that's not enough to be the new organ, but the old organ has been removed so they no longer have it. Then what?