male-looking anatomy
A nitpick: it is not male-looking anatomy, it is male anatomy.
perfectly matched additional responsibility
Which responsibility? If I am of whatever gender I say I am, I can change genders at will. I am not "barred" from the other changing room any more than picking one door to walk through "bars" me from the other door.
Nice steelmanning
That didn't involve transmuting your position into either steel or straw. That was just me amusing myself :-) I did not mean to imply anything about your views on widespread surveillance.
But I'm a bit confused now about what your position
I don't have a well-developed position delineated by bright lines. Basically you have a conflict between two groups -- let's call them "trans" and "mainstream". Such a conflict is nothing unusual and, indeed, the entirely normal state of a human society. Typically such conflicts are resolved according the the balance of power between the groups -- the results vary from one side fully suppressing the other to an equally-unsatisfying compromise. Occasionally the stars align and it turns out that the conflict is easily fixable and can be "dissolved" in LW lingo.
In contemporary Western societies such conflicts are usually resolved politically which means that the sides wage a cultural war "for the hearts and minds". This kind of war uses propaganda as weapons. Accordingly, the war involves loud screaming about morals, justice, fairness, God's will, etc. etc. -- whatever is needed for the agitprop needs of the day. I tend to by very cynical about such agitprop.
Note, by the way, that a completely general answer to the there-is-a-tranny-in-my-shower problem does not exist. As you yourself observed, it all depends on the local culture. A good solution for the showers in San Francisco's Castro district is likely to be different from a solution for downtown Salt Lake City -- and that's even staying inside one country.
it is male anatomy
What's visible to, and possibly disturbing for, the people in the changing room is what it looks like. I don't know, e.g., whether you would consider a post-op female-to-male transsexual person's anatomy male or merely male-looking, but I take it it would be about as disturbing in that context as a straightforwardly cis man's. So the relevant question is what it looks like.
I can change genders at will
I am pretty sure no one is in fact proposing that people be able to change their gender at will simply by saying "I'm a woman no...
There are some long lists of false beliefs that programmers hold. isn't because programmers are especially likely to be more wrong than anyone else, it's just that programming offers a better opportunity than most people get to find out how incomplete their model of the world is.
I'm posting about this here, not just because this information has a decent chance of being both entertaining and useful, but because LWers try to figure things out from relatively simple principles-- who knows what simplifying assumptions might be tripping us up?
The classic (and I think the first) was about names. There have been a few more lists created since then.
Time. And time zones. Crowd-sourced time errors.
Addresses. Possibly more about addresses. I haven't compared the lists.
Gender. This is so short I assume it's seriously incomplete.
Networks. Weirdly, there is no list of falsehoods programmers believe about html (or at least a fast search didn't turn anything up). Don't trust the words in the url.
Distributed computing Build systems.
Poem about character conversion.
I got started on the subject because of this about testing your code, which was posted by Andrew Ducker.