I wonder about the same thing. I have a bit of an androgynous look, and sometimes when the weather is cool and I'm dressed in jeans, motorcycle boots, hoodie, and have my hair up under a beenie, someone will refer to me with a male pronoun until I say something. Then they apologize profusely. It's an honest mistake and doesn't offend me in the slightest!! If I really wanted to be sure the entire world could tell my gender from any distance, I'd dress girly all the time.   These people just love to complain and be a victim.