Let's stop beating around the bush; a proof does not create equivalence; it reveals it. The equivalence between sensitivities based on the fixed point and those based on KKT is an inherent property, not an invention. Confusing this is like claiming that our financial models create market dynamics instead of understanding them. Take the example of the Bank of Japan: its policies revealed existing sensitivities in the bond markets; they did not generate them. We must decide to recognize that the proof validates a pre-existing truth.