Your rhetoric extracts meaning from any sort of argument that is not based on "empirical categories". Rather than address it directly, I'd like to outline how it can apply to other factors as well:
"Slavery" and "freedom" are constructed similarly in narratives. We call the CSA's subjugation of black people as "inappropriate" because we subscribe to the belief that humans cannot be owned as property and that the masters did not have the "right" to execute authority over what they believed to be their own property. The USA's terms of property were actually quite similar, that people should be free to use property as they deem fit; they only disagreed with whether people could be property.
The same rhetoric, Traitorfish, that you used to deconstruct the German invasion of Poland can be similarly used to deconstruct other moral quandaries, even though my attempt to do so above may have been insufficient or non-parallel.
- From whence come inalienable rights? Any narrative could be constructed to provide or withhold freedom from subjects and actors.
- Why should chemical and biological weapons be banned? It can be empirically proven that pain is usually greater when such weapons are used, but why is the distinction of "pain" a meaningful one?
And so on. If we subscribe to the "moral relativism" theory, then discussions of moral truths become difficult and/or meaningless. If we subscribe to "moral absolutism", in that there is an absolute moral truth, then there
is a correct answer as to which, if not equal, of two parties is more in the wrong. Our task is then to parse the information we have and the moral truths we've estimated to date to arrive at a moral judgement.
What narratives
can be constructed is again irrelevant. What matter is what narratives
we construct. Where "we" means our philosophy and ethical structures that we have created to date. Empiricism is lacking in countless situations. It should not be a prerequisite.