People, for the most part, are just woefully ignorant when it comes to the T community. I know some college instructors who have put forth a question on gender to their students and get all kinds of surprises. I also know a few researchers (sociology) who have mentioned that they have a T friend (me) and have colleagues ask a ton of questions because they have simply never really met a T person before.
It carries over in other areas. There is a pretty strong T presence where I live and yet I have had medical doctors ask me a lot of questions and tell me that they have never had the opportunity to discuss transsexual issues with anyone else before. I still get charged for the time, that I think needs to change.

Now imagine people who have not had to think about gender much and also lack a college degree of some sort.