Obama only tried to close Guantanamo by moving the prisoners to the United States, which is arguably worse than having them in Guantanamo. It would mean that you could hold prisoners in the United States indefinitely without trial. What he should have done was give the prisoners fair trials or release them.

Having prisoners in the US is a lot more hassle and subject to scrutiny than keeping them tucked away on some out of bounds military prison where few have access to, which was probably the reason to put prisoners there in the first place. Anything could be done to prisoners on Guantanamo, including torture.