I think that's why it means a bit to me, watching him experience waterboarding in a controlled environment, and explaining how he felt, and that it is torture. Love him or hate him, he's a damn good writer and lets you know exactly what went on, and perhaps still is, in the sense of how the sensation stayed with him:
Steeling myself to remember what it had been like last time, and to learn from the previous panic attack, I fought down the first, and some of the second, wave of nausea and terror but soon found that I was an abject prisoner of my gag reflex. The interrogators would hardly have had time to ask me any questions, and I knew that I would quite readily have agreed to supply any answer. I still feel ashamed when I think about it. Also, in case it’s of interest, I have since woken up trying to push the bedcovers off my face, and if I do anything that makes me short of breath I find myself clawing at the air with a horrible sensation of smothering and claustrophobia. No doubt this will pass. As if detecting my misery and shame, one of my interrogators comfortingly said, “Any time is a long time when you’re breathing water.” I could have hugged him for saying so, and just then I was hit with a ghastly sense of the sadomasochistic dimension that underlies the relationship between the torturer and the tortured. I apply the Abraham Lincoln test for moral casuistry: “If slavery is not wrong, nothing is wrong.” Well, then, if waterboarding does not constitute torture, then there is no such thing as torture.Believe Me, It's Torture
If it were a piece of cake, he'd have said as much. But even with a controlled situation where he knows he can stop it, and even being a person I don't see as particularly squeamish, what he experienced just sounds ghastly, and I am more convinced having seen the video, that it's not really something governments should do--period.