The twins treated commoners well and did not like calling Emily and Jacob as slaves or treating them like one.
However, their mindset and actions were different from what was expected of them by people in their surroundings. They were whispered about as sullied disgraces, accused of adopting a commoner mindset after their years of living among them.
Meanwhile, their supposedly "unsullied" siblings, who, in their perspective were cruel to slaves and often behaved far worse, received preferential treatment from the nobles.
These stark differences in treatment further enlightened the twins about the unfair practices deeply rooted in their kingdom.
Sebastian and Seraphina were further enlightened when their father, taking pity on them and wishing to give them a break from all the judgment, allowed them to accompany him to the Yearly Assembly in Medeus, despite Queen Trisha's protests.