Thank you for expanding on my admittedly rushed comment. I agree that comparing health data in the US to that of developing countries is problematic. But it raises interesting questions.

One question, that I don't think has been answered sufficiently is that the controlled trials and published studies have been criticized for possibly overstating the effectiveness of treatment. (The trials were stopped early on ethical grounds which can overestimate the effects being tested.) Wikipedia has a fairly comprehensive roundup: http://en.wikipedia.org/wiki/Circumcision_and_HIV#Randomised...

I think my bigger point, though, is that it's easy to look at data and say, "Aha! This one thing is the solution" without stepping back and looking at all the different pieces that make up the big picture. It's going to take some combination of education, prevention, vaccination, and health policy to tackle this disease.