"Um, Afghans are not Arabs."
Not as accurate but easier to get the generally racist point across than saying that defending Ukraine but not Afghanistan makes it look like we are racist because we'll defend white people but not Pashtuns, Tajiks, Hazaras, Uzbeks, Nuristanis, Aimaqs, Turkmen, Balochs, Pashai, Nuristani, Gujjars, Brahui, Qizilbash, Pamiri, Kyrgyz, Sadats, some others, and even a few actual Arabs.