I don't think the movie was about sending a message so being for or against is appropriately up to the audience to decide. The critcism from both the left and the right says it was probably done the correct way.
I didn't go watch Zero Dark Thirty looking to confirm or deny what I believe. Separately the controversy is a whole other issue. I like the controversy only because it shows who people are. It's a rorschach test. The people who used the popularity of the TV show "24" saying Americans were okay with torture are the very people questioning the torture aspect in this movie as to say torture didn't serve to find Osama Bin Laden. All of the sudden they're now against torture when they were bragging about how it worked before? Why? Then you have leftists like Ed Asner and Martin Sheen telling Oscar voters not to vote for the movie as best picture because they claim it glorifies the use of torture. That's what makes the movie great because it's thought-provoking and both the left and right and their agendas don't like it.
The right loves the TV show 24 because they believe torture gets results. But for some reason they hate Zero Dark Thirty when they get a bigger payoff with the death of Osama Bin Laden. Django Unchained gets criticism for violence but some more violent movies like the Expendables or Arnold Schwarzenegger's upcoming violent movie The Last Stand does not? The NRA faults movies and video games for Sandy Hook so the organization thinks guns shouldn't be blamed. By the same logic the NRA uses that it's only a irresponsible few that abuse the use of guns so there shouldn't be any regulation, the same can be said of movies and video games. Not everyone that watches a violent movie or plays a video game goes out and shoots and kills kids at a school. The contradictions says it's all a distraction and partisan politcs as usual behind it all.
Then you have the left. Martin Sheen doesn't like Zero Dark Thirty because it makes torture seem all right? So Kathryn Bigelow has to send a leftist message of his liking? The same Martin Sheen that helped out his economist friend Peter Navarro make racism all right by narrating in his documentary Death By China filled with lies about trade between China and the US. I guess at least Sheen is being consistent when he doesn't want the truth to be told. Yeah what happen to all those leftists in Hollywood who don't like Chinese investment into their industry because they think China will interfere with the director's vision?
What both sides have in common is they both want to hide the truth and maybe more damning is they think Americans can't think for themselves. Why not depict torture how it really is? Why not depict history how it really was? Is there something wrong with the truth being depicted plain and simple?
Honestly, you have lost me with most of the above and how it relates to the topic, but my biggest problem with the movie, as I have already explained, is precisely because it inverts the reality of how things happened while purporting to be 'documentary like'.
Torture yielded no useable intelligence that aided in the killing of OBL, that is as plain and indisputable a fact as you can get when it comes to covert ops like this.
The central role torture played in finding OBL as portrayed in the film is a complete fabrication, yet, we have normally well informed and intelligent people like yourself coming away after watching the film and believe feverently that torture did directly lead to the death of OBL despite it being a complete lie. Such inversions of fact and lies do not happen by accident.
If Bigelow had actually stuck to the facts, far far fewer people would have so much of a problem with the film. The reason people from both left and right at attacking the film is because there are very serious issues with it and how it was marketed.
It is interesting that you bring up 24, because in 24, while Jack does engage in torture, and it was quite a revelation when it was first aired, you never get any hint that Jack enjoyed inflicting the pain it caused, in fact, you get the feeling Jack hated the torture almost as much as the people he was torturing. In ZDT, the guys doing the torture relished it, and in playing the 9/11 tapes right at the start, Bigelow was shamelessly exploiting the pain and anguish that is still raw in the hearts of millions and perverted that into getting the American audience to join-in in taking pleasure from seeing people tortured, as a measure of payback for 9/11, and in many many cases, it worked. That is well calculated and no accident.
It is also interesting that you are defending Bigelow as if she was someone just trying to tell the unvarnished truth and attacking her critics for wanted to push their own agenda into the story of the film, when in fact, it is Bigelow who is pushing her own agenda on the audience, at the expense of the facts. Her genius lies in the skill with which she pushed her message to get people into believing she had no message to send and that everything was as it actually happened.
ZDT is a propaganda piece white-washing American torture as necessary and effective, and Bigelow shamelessly exploited 9/11, the death of OBL as well as numerous other terrorist attacks to make her audience more susceptible to her agenda by turning the pain, grief, longing for justice and relief/joy people feel for the victims of those attacks and the death of OBL and twisting it into the most ugly of all human emotions - sadism.
Incidentally, that is also why so many people have issues with later Tarantino films, not in the depiction of the actual violence, but more in the motivation that drives that violence and the pleasure his characters derive from inflicting needless and excessive suffering.