They are living medieval times, apparently under a feudal system to boot. I don't know how virtuous you are expecting them to be, but clearly Maou and Hero are more so than most. You are also badmouthing Maou far too much; if her goal is to end the endless war and replace the war dependent economics, I don't know how that's as bad as you make it sound like by saying she's trying to cram her own values down everybody else's throats. Some feudal countries of the old had the famous system in place that if a serf escaped their fief to a citystate and managed to avoid trouble and capture for a year, they would become free citizens of the city. If this land Maou chose has such a law in place, those two might in fact become free people in addition to gaining education and experience in Maou's service. No matter how you look at it, it must be a better choice than walking heedlessly into a random big city they know nothing of and hope for the best.