Even if every single person held hostage at Guantanamo was directly involved in a terrorist attack they should not be tortured and detained forever without a proper trial. Revenge achieves nothing but more suffering. What has been done can never be changed but we can ensure that no more innocent will be hurt by setting the bar high enough so that even people proven guilty are not treated like sub humans. How we treat the worst people in our society sets the bar for the innocents inadvertently caught in the cogs of the judicial system.
It is better that 10 guilty persons escape than 1 innocent suffers https://en.m.wikipedia.org/wiki/Blackstone%27s_ratio