"Kind" huh. I guess in her own way, the mother still cares for our protagonist. Even though she's controlling like that, from my point of view anyway, it's her own way of keeping her family together. With the man of the house down and the rumors surrounding the Duke, she can't afford to be kind or too accepting of him or else it could lead to trouble. It's the same for the other siblings too. If something happens, they need to be ready to pick up the pieces by learning proper etiquette and making friends in high places. All of this drama can be resolved if the Duke manages to break down the curse, an option that the mother is probably hoping for. I mean, why else would she be so lenient towards the Duke and Viola? Despite all the harsh criticisms, the siblings still have a remarkable amount of freedom. With how things are, it would be easy to transition back to the status quo once the Duke gets better.