Who are all these people who cannot discern a person's sex just by looking at them?
In person, people who are transgender are usually very obvious. My son has a female best friend. She has transitioned, has a beard, wears clothes bought from the boys section and yet is still very obviously female. She doesn't even look like a short man. She looks like a woman with a fake beard. Which let's face it, is entirely what she is.
Likewise men who think they pass. They don't. Not even 'well known' transwomen in the public eye. You can see how they stoop when standing for photos, etc. trying to make themselves look smaller. Their gait is visibly male. This can't be changed.
It's time to stop pretending that people can't tell and just accept that some people like to present as the opposite sex and that's fine for them but it doesn't change their sex and they are not above the law.