Since when, outside of Hollywood films, was rape considered acceptable in Medieval times? I don't know about the Continent of Europe but England had laws. Sure some nobles probably acted as though they were above the law but it was there. Henry II accepted a public flogging as his penance for his part in the death of Thomas Beckett. Can you see the Chantry making any noble, much less the Empress Celene, endure a public penance for their part in the death of someone? Yet murder is condemned in the Chant of Light. (Strangely enough rape is not mentioned).
In Thedas there seems to be one law for the nobles, one law for the human commoners and virtually nothing for the elves. And for some reason it would appear that rape is not considered a particularly serious crime by either the Chantry or the Law Enforcement officers, presumably because the Maker forgot to mention it. If I am allowed, and I dare say it will not, my first act as Inquisitor would be to declare the morality of the Chant of Light as applying to all, high or low, just as it says and ensure that Justice is applied evenly across the social classes, no matter what your race. As for Divine Right to do anything, that would be officially abolished.