I'm a pre-applicant, so please take my comments with a grain of salt, but I think you are absolutely fine. The comment you are asking about is referring to a staircase analogy many of us like which says that we all enter the admissions staircase on a different step, and if you are on a lower step, you need to excel in the interview in order to climb to the level necessary to receive an A.
I happen to think that your "URM, disadvantaged with good ECs" status probably puts you on a higher step than would otherwise be indicated by your stats, so this "greater than great" performance requirement doesn't apply to you. In any event, your point is very well taken -- you are who you are and can only do you best, even if it's not good enough.
I don't think it's accurate, or productive, to think in terms of needing to be something other than your honest self, or to be "greater than great" in order to have a real shot at an A. You are already "greater than great" - you scored an II at a T5!!!!! Now just be yourself and go close the deal. 😎