why are they still treated as if they are, shackled even when alone and watching television?Because the government is stupid and evil and because treating the detainees fairly is politically impossible. Everytime an idiot congressman visits Gitmo and sees humane treatment, he can pitch a fit about how the administration is soft on terror. That helps him politically because most voters hear Gitmo and think 'Osama's best buddies'. That political constraint puts a ceiling on how well the Gitmo detainees can be treated.
This is obviously horribly immoral. That being said, I don't know how to fix that problem.
The real problem here is that most Americans, especially most red-state Americans, believe that Gitmo detainees are dangerous monsters rather than just a bunch of guest workers who were in the wrong place at the wrong time plus a few low-ranking fighters. If you fixed this problem, Gitmo would cease to be an issue because there'd be no political benefit to opposing humane treatment or settlement in the US.
Wouldn't it be much more cost-effective to provide some relocation assistance?
Sure. Where would you relocate them to? I mean, the government has been trying but most countries are not interested in taking these people, even though most of them have done precisely nothing wrong.
without exploring other options
I'd love better options. Can you suggest any?
Seriously, all the options I see suck and are unjust. If you have any suggestions I really, honestly, would love to hear them. But I haven't seen any yet.