...that's just moronic.
If you're torturing someone who doesn't have the information you need - an innocent - then you are committing an atrocity for no good reason, and the only way they can stop it is by lying. You will cause mental trauma, possibly even drive them insane, and cause them to hate you. You have now just made a new enemy, possibly causing them to join "Team Terror".
You just lost the game, and let the terrorists win by doing that. That being said, when they turn your country into a dictatorship with a ruler who relies on fear, and people are too scared to live their lives normally, the terrorists have already won.
So, we get someone who does have the information. Let's use the same example that pro-torture people love to use: they hid an atom bomb somewhere below the city. So, you know for a fact that this person knows the location. In one hour, it's going to explode if you can't find and disarm it. What do you do?
That person is willing to blow a city up. They're probably insane at this point. They might very well be willing to die or undergo an hour of torture just for their goals to be achieved. So you still don't get the info - torture isn't helping you here.
But they don't even have to be willing to undergo that. They could, you know, lie. Seeing as an innocent you're torturing certainly will lie for it to stop - and let's face it, they will because it's the only option they have - an actual terrorist will do the same thing, both to end/pause the torture or to mess you around. So, time is ticking. They say the bomb is under the monument. Half an hour is wasted deploying people there and searching the area. You torture them some more and they say "Okay okay, it's under the primary school."
You waste another half hour, and guess what? It was under the hospital. Game over. Once again, your torture had zero effect.
Of course, if you are willing to torture people, then your enemies are also going to be willing to do it to you. Every time you commit an atrocity against them, you are fuelling their hatred, providing them with martyrs, proving to them that you actually are the bad guy they think you are, and also convincing the rest of the world that they shouldn't help you.
There are records and statistics that back up what I say, but frankly, I can't be bothered searching for them when the other person is likely to just say "Nah, I still think you're wrong, and those statistics are lies invented by communists!"
So, torture makes more enemies, and almost never succeeds. Most people know this, and yet a few countries still do it. There are really only two reasons this could be:
1. To be "the bad guys". To scare others just on principle - especially to control their own innocent populace with fear.
2. For their own sick pleasure. The people who order these things to be done? I just bet they're beating off under the table.