>Do humans not fit the standards for being broken into multiple subspecies?

No. Multiple human subspecies did once exist (examples being Neanderthals, Denisovans, Homo Erectus, and Homo Floresiensis) but only our species, Homo Sapiens, remains (with traces of Neanderthal DNA so there was some interbreeding.) However race is a cultural and social construct. Different human races are not different human subspecies. A Pygmy, a Norwegian, a Sentinel Islander, and a Han Chinese person are all the same species. The superficial variations in average height, skin color, etc. do not vary enough to constitute species differentiation - humans share 99.9% of their DNA, and the vast majority of genetic variation exists within populations (in other words, within "races") and not between them.