Also, the Tevinter Imperium is the Qunari's archnemesis and has been for hundreds of years at this point, so for Sten to be ok with a powerful member of the Imperium to walk out with a bunch of slaves is truly baffling.
The same Sten that in almost all cases aggressively favors a fight and in the quest immediately prior to this one, suffers a steep disapproval drop if you surrender to Cauthrien instead of fighting. Sten has several reactions that badly derail his established characterization:
At the end of the quest to investigate the elven alienage in Denerim, you discover that a powerful Tevinter blood mage has been in charge of trafficking elven slaves back to the Tevinter homeland.
