My OH reading Roald Dahl to our daughter - in the twits she is a horrible person and it shows on her face as she's ugly - but we contextualise this, similarly the way people treat each other "that's not a good way for a husband and wife to treat each other".
I don't think there's a right way to do this, but yeah - life is complex and Roald Dahl's books show people dealing with arseholes, and often winning - the horrible people in these stories need to be horrible, but more context is helpful.