If Rockstar Games produced a game about the battle of Stalingrad I would expect civilians.
Realistically, civilians were prevalent during the battle of Stalingrad. Civilians were prevalent in many battles during the Second World War. It is simply unnecessary to have civilians in a game that focuses primarily on military combat, even if realistically such combat afflicted civilians in the sense they fought or were innocent bystanders.
Rats, birds, cows, chickens, fishes, and all sorts of rodents were around Stalingrad as well. Should we have them modeled as well? (Not trying to be condescending). Point is, in my opinion, having civilians would not add any depth to the game.