Spock may be counting just the Allied
I mean who cares how many Germans or Russians
Well maybe in the 60s when the Cold War was in full swing. When no Chinese actors were actually allowed in TOS. I think nowadays after 60 years we can consider every death, even those of 'our' enemies.
China and Russia were part of the allied forces in both WWI and WWII. Allied deaths would include Chinese and Russian casualties.