I have a problem with such statements, as they blithely link an issue of value with one of efficacy. It seems as though it should be enough to say, torture is un-American, or more accurately in my opinion, an offence against our humanity. If one feels it necessary to add, "oh, and it also doesn't work," it seems to leave the door open for debates on what level of efficacy would justify torture.
To condemn torture purely on the grounds of efficacy seems tantamount to saying that 9/11 was immoral because it failed to secure peace in the Middle East, rather than because the act itself was a monstrous failure of humans to be human. On the other hand, this argument of efficacy provides an unsettling explanation on how 9/11 can be differentiated from Hiroshima and Nagasaki. I guess the first casualty of war is usually humanity, rather than humans (more on that if I ever finish my second Hunger Games post).
Granted, the bomber and the 100% accurate torture does make an interesting thought experiment. However, out here in the real world I think I can safely conclude I am 100% against torture. Intellectually at least, there are times when my emotions say different, but my humanity is damaged just like everyone else's.