>Similarly to biological evolution, on any sufficiently long time scale the descendents aren't more advanced, simply better adapted to different conditions. Our ancestors' societies reflected wildly different contraints and path dependence, not primitiveness.

I understand what you mean, yet I refuse to call concepts like universal human rights, rule of law and the unacceptability of war crimes as simply different adaptations, as opposed to being strictly more advanced than the predecessor ideas.

That's fine, you can take whatever moral stance you want. It just doesn't have any place in scientific discussion.