Then I guess the guy won't have to plunder then. Maybe they changed it from BETA as there was a guy stuck on that quest there because of acquire a province or plunder (and he'd already completed the map).
I, too, was a little surprised that I did have to plunder to finish this quest as I have finished all sectors in the continent map. In the past, the use of the word "or" gave an autocomplete if one of the actions was not possible to do because all of that action had been completed prior.