Well it is a system a system of torture and lets be frank any form of imprisonment is torture, even if SHU is much more so. But you failed to answer the question posed, should prisoners subjected to solitary torture, be released because it is inhumane to do? or just manning because he is special.
There are more 'human' ways of imprisoning people, even in isolation regime. I thought it was implicit in my reply but, yes, I think all persons subjected to any type of torture must be released. I'm still ingenuous enough to think torture and democracy are incompatible concepts. On the other hand, everybody knows the imprisonment methods used in places like Guantanamo, so scepticism on the humanitarianism of certain governments is legitimate.