Just because what happens in our training isn't torture doesn't mean the same TACTIC cannot be torture.
Here's the thing: nobody in our own training BELIEVES he is in enemy hands. The military will tell you themselves that one of the most important things for a soldier, and for an army, is BELIEF. The army that BELIEVES is worth 10 times its same force without that believing.
The only way to truly simulate waterboarding, as has been done by the US military, is for the waterboarded to believe he is in enemy hands. Anyone on any training knows HE WON'T be horribly disfigured, HE WILL BE LOOKED AFTER medically, the suffering WILL END and will end WELL, he won't be tortured to death, etc.