Backstory question: Only six million?

[Exposure]

As someone pointed out to me over an IRC chat about the backstory of UFO alien invasion:

<havocfett>   And then, in its civil war
   <havocfett>   takes a total of six million casualties
   <havocfett>   Despite /nuking/ /itself/
   <havocfett>   Evidently /repeatedly/
   <havocfett>   six million
   <havocfett>   Out o over a billion

That number of casualties for the Chinese Civil War seem just a tad off, don't you think?

[Snowblind]

Story says they used tactical (low-yield) nukes for limited military purposes some of which were cities, not a full-on nuclear exchange.

6 million people is a lot of people considering how most conflicts in modern war get up into maybe 4 or 5 digits.