A blind listening test is not a test for bias.
It shows that listening under those conditions is mostly more difficult, but it does not explain WHY it is more difficult. People are quick to jump on the bias train, but this may not be correct.
Also it may be a bit pedantic to assume that experienced audiophiles can’t distinguish between music mode and analytical mode.
Also, why would Amir not be biased himself? Maybe he does not want to hear (or accept) a difference?
Also, as we still not completely sure WHY we experience differences in cables, who is to say he is even measuring the right parameters? What if our brain can detect the differences? How will we measure that?
To be clear: I am not saying he is wrong, but I am suggesting that there are too many questions left unanswered to conclude that he is right.