I think the point is, ethical progress (be it through abolition of slavery or greater tolerance of difference) should lead to a greater positive effect on the s

I think the point is, ethical progress (be it through abolition of slavery or greater tolerance of difference) should lead to a greater positive effect on the status quo. If other forms of social, economic and political injustice take the place of previous abominations, the net result is a state which appears disinterested in positively affecting its ethical standing on the world stage.