1. In thought
they seem to be conceptual opposites with many gradations in between.
2. They are not solely subjective; we have rules and definitions to determine at least whether warfare is being conducted.
3. If they were the same thing, it would be difficult to account for the common conception that they were opposites. What seems to be happening is that, as in many instances in the human world, the further the situation strays from one of the opposite categories, the more subjective putting the situation into one of the concepts becomes. Additionally, the role of political propaganda, especially by warring parties, often confuses the issue.