The above argument is not whataboutism. The statement "the US is basically doing a fantastic job of fucking up antibiotics for everyone" is false because no policy change in the US will significantly affect the rate at which resistant strains appear worldwide, US antibiotics consumption being less than 3% of China's. This refutes the original argument by bringing in additional information, whereas whataboutism is defined as changing the subject "without directly refuting or disproving the opponent's initial argument."