I'm sorry, my experience leads me to think of this as mostly baloney.
First of all, the unstated fallacy running all through this discussion is that you will get the same predetermined reactions depending on whether you're "passable" or "unpassable." That's what trips my baloney alarm. The world has a wide variety of people with a wide variety of mindsets and perceptions. It isn't all black or white. I get a range of reactions to my femaleness which cannot be all predetermined by my looks.
I'm not the most passable dame in the world, but my feminine nature is so pronounced, that's what most people pick up on. I see this constantly, interacting in public and meeting new people: more than half, I'd say, respond positively to my femaleness in a way that's natural, not forced-- something they sense intuitively. More women than men get it, but lots of men get it too--even guys I knew back when I had a beard and all.
When women meet me, their sense of shared sisterhood kicks in and they speak girl-talk to me as they're used to speaking to other women--it's basically automatic. When gentlemen meet me, their sense of chivalry kicks in. They even kiss me in greeting, which they would never do with another guy. It feels completely natural too, not feigned for the sake of politeness. You can tell the difference.
Then there are the individuals who don't get it, but they're in the minority, in my personal experience. And many other people are neutral--maybe they're the sort who say they don't care about gender one way or the other, they just think of people as individuals. So I just have to say the attitudes expressed in this thread strike me as pretty unrealistic, the assumption that it has to be all one way or all the other. I have a vantage point on this because I look good enough to pass some of the time, but most of the time I probably don't. My experience has shown that looks aren't everything that determines how we present in society. My vibes are distinctly feminine, and that counts for something in the total presentation, as others in this discussion have noted.
Chris is right. Chris, I love what you said and how you said it. You always remind me of what I like about men at their best. 🙂 Blunt, plainspoken, maybe a little gruff, but with profound sympathy for other human beings and a good heart.