Talking about someone having 'been beaten' by US while China literally puts 100's of thousands in concentration camps merely for being of a specific ethnicity ... as their organs are nabbed by the elite via 'body part' black markets.
All these issues have to be put in context: the scale, the type of abuses, the proportionality, the context, the risk etc..
9/11 was a 'very scary' moment in history, the likelihood that others were planning to do the same was very high, and legit terrorist organizations were operating around the world.
The response to 'non-uniformed irregular attack' was necessarily going to have to be equally as asymmetric, i.e. getting at bad people in the locations they were working form, as opposed to a battle field.
It gets a little bit pedantic to discuss 'human rights' when in conflict, people are exterminated 'in accordance with all UN/International laws and rules' sometimes pretty arbitrarily. For example, the teenager Omar Khadr who killed a US Medic on the battlefield was injured, and about to die. It was US special forces who them saved him, ironically so he could spend a long time in Guantanamo.
The paradox of the fact that were he not of 'special interest' - he would be 100% dead, and nobody, not 'Amnesty International' or the UN would put up a fuss, as he was shot lobbing grenades at medics.
US and EU laws are not designed for acute, wartime scenarios, the only real question is how rational and reasonable the management of force can be applied without breaking too many humane boundaries, and, how many 'mistakes' we are willing to make.
The CIA black cells are definitely a stain, but in the grand scheme of history, it's nothing. Civil, lawful and humane order was otherwise broadly maintained.