The thing about a war like this, is that while saving individual civilians is all well and good, you have to look at the bigger picture. Azeroth was losing this battle by the sheer nature that the Legion regenerated their forces, and the armies of Azeroth did not. It was not sustainable to stand and fight against the Legion on a fair playing field, because they would always win.

To go back to the battleground analogy, it doesn't matter how many Horde players you kill on the road. If you ignore the objectives, they will still win the battleground because you're too busy fighting enemies that will just keep resurrecting.

If everyone had been like Jainia, we would have lost the Legion War, because we would have stood blindly fighting the demons wherever they brought the battle to us, and would have been gradually overwhelmed as we made no advances to put them on the defensive.

Jainia might have saved a village or two, but how many more villages would have been saved if she'd helped stop the legion earlier in the war.