I think it would be hard to argue that this movie would have been anywhere near as effective if the subject weren't female, attractive, and presumably innocent of a rather trivial crime (revolutionary thought?)
In an age where everyone tries to lump coercive interrogation into the same ball, I think that's an important distinction to make.
I'm rather confused by what you are saying here.... are you saying that audience members would not object to the way in which The Interrogator tortures The Author, physically and mentally, if she wasn't female, attractive and innocent???? Or are you saying the film would not be as emotionally moving???
If that is what you are suggesting, then, speaking for myself, I think you are wrong.
If the character of The Author was an unattractive male, then I would still find The Interrogator's actions morally repugnant.I find it rather insulting that you imagine Madeleine Stowe's "attractiveness" is even a relevant issue in the minds of most viewers, I'm sure most sane people are capable of empathising with someone, even if they are not good looking. I think it's sexist to say that people would only feel sorry for The Author because she's a woman, I'm sure the people who sympathise with her character do so because she is made to undergo a harrowing experience, gender is irrelevant.
If the character of The Author was actually GUILTY of writing a subversive anti-government allegory disguised as a children's story, something in the style of Orwell's "Animal Farm", then that would not be considered a "trivial" matter in most totalitarian societies.... and totalitarian societies do exist in the real world. Indeed, your calling it a "trivial" crime underestimates the kind of ruthlessness that people acting in a dogmatic, fundamentalist mindset are capable of... we live in a world where people gather en masse to call for the beheading of cartoonists.
But OK, let's say The Author was an unattractive male who was actually guilty of being a violent resistance fighter. I don't believe that would justify The Interrogator's behaviour - much of the physical and mental pain he inflicts upon The Author strikes me as gratuitous, calculated more to satisfy his lusts or give him a "power trip" high, rather than serving any constructive purpose.
As to the question of wether the film would be less emotionally moving if The Author was guilty, given the skill of the director and the actors, I think it would be equally moving, but perhaps in a different way. Perhaps the viewer would be less inclined to sympathise with The Author, but I doubt they would be unaffected by the drama.
And your statement that "everyone tries to lump coercive interrogation into the same ball" is a pretty crass generalisation. I don't think that is at all true, many people argue that coercive interrogation is justified under certain circumstances, and it is a view that is reflected in a lot of mainstream entertainment media nowadays - such as the TV show, "24", and the movie, "Taken".
Finally, I don't think the intended message of "Closet Land" is that "TORTURE IS BAD"... I believe it is a film with multiple layers of meaning, rather than being simply a political tract.