CBT is notoriously useless for clients who have a history of developmental trauma. I find it interesting that your mind came up with such extreme examples when trying to think of the positive affirmations (such as your concentration camp scenario). It's almost like your mind it trying to let you know that the experiences and trauma you are grappling with are far, far beyond the scope of CBT... or that you were gobsmacked by the absolute uselessness of it in your particular situation.

I've experienced that same feeling a couple of times. Once a therapist told me that because I had agreed with a positive comment he had made about me we had 'won half of the battle' and were 'nearing the end of our work together'. I was speechless. He obviously had no blinking idea what he was dealing with!