You're missing the point. The U.S. signed the Geneva Convention. The only reason why Gitmo is not opening up the Human Rights Tribunal to go after the United States is because Gitmo falls out of the signatory regions, that's it. It's a grey area, legally speaking. Morally speaking, we all know what's going on there and that it's against everything the United States says it stands for. The point is that we are supposed to be above this gulag behavior, not partaking in it.
More than likely, Gitmo is a place where top U.S. informants are being held, otherwise they would spill the beans to the whole western media about this entire corrupt operation. Keep your friends close but your enemies closer, etc.
Look at the position the U.S. government is in. We can't let them go because, yes, they will run right to the nearest rebels and tell horror stories of OUR dishonor, which will just embolden our enemies. Yet the government won't just try them in U.S. courts because they will air ALL of our dirty laundry.
The people in Gitmo will be, in some form or another, in our custody forever, probably until they die. The other options present huge risks to the government. Forget our national "safety", it's not about that. Our safety was blown years ago. This is about protecting the asses of our government. If we knew half of their dirty ops, there would be a revolution tomorrow.