This is a cop out argument that can be made for literally any comparison ever. "Thing A is not identical to thing B" is true for literally every A and B you choose to define in the universe, and "thing A is identical to thing A" is a pointless, self-evident comparison, so either you're discounting the entire concept of making comparisons, or you're going to need to make a better argument for why "Action X, applied to thing A, which produced effect Y would not produce effect N if applied to thing B". "Thing A is not identical to thing B" isn't a real argument.

I'm sorry if that was wordy, I'm just sick of this lazy argument against comparisons as a concept when people don't like the idea behind a comparison.