I understand it's an "odd"' picture for someone to see, but once you understand the situation is makes sense. The picture represents a very rare occurrence, in which people over-react to in my opinion.
Quick story. I was in Lowe's a month or so ago, and I went to use the men's room. I'm standing at a urinal, doing my business, when a woman (clearly identifying herself as a woman, she was wearing jeans and a long sleeve shirt, but she looked like a woman) comes up next to the urinal next to me to do her business. If I was younger, or stupider, I may have made some stupid comment or asked a question to her, but I decided otherwise. In the end, it was 2 people just trying to use the restroom and then getting on with our day. I assume that's how most people (transgender or not) want to live their lives. They want to just live their lives as normal as possible. They don't go use opposite sex bathrooms to get a sexual thrill out of it, they do it to do their bodily functions and move on.