In a way you are both right.

Winning a civil war requires actions that have ugly consequences, and afterwords we will have to live with them and face those consequences.

Sticking to moral behavior is admirable, but it is dangerous to try and convince ourselves that we can come out of a civil war with our humanity intact. History has very few examples of that happening.

If we don't consider the fact that our morality and humanity will be compromised by any civil conflict, then we are failing to fully consider the costs of our actions when marching toward that conflict.

This, in turn, causes us to undervalue the avoidance of said conflict. If we can't find a peaceful resolution, there is a good chance that our souls get sacrificed along with our bodies.