I am not a historian or a time traveler ( but I’d love to be a time traveler) but I’ve read a lot of old books. In those days they had very strong ideas about manners, about class status, and about personal honor. There were rules about how you addressed someone even in bitter disagreements. Insults were common but there were lines you could not cross. Not recognizing someone by their name and title was deliberately disrespectful and rude in a way that demanded “ satisfaction” …. In essence when someone crossed that line and insulted your honor the rules of civil society demanded you duel, and duels were deadly affairs.