I think what Terri Hatcher is trying to say is that portraying a Over-Realistic parent is hard because it can fall into either borderline narcissist or Lucy Van Pelt and I think she did not want to go the Lucy route because she did not want the real mother to be too harsh. If she was even harder then it would of made the Other Mother's movitvies even more harmful and expoitive of children who do deal with Over Realist parents and parenting because that's what groomers in real life do.

They prey on a child's insecurites to make the child comforted and hide the other victums under the rug.