The rules were her only way to gain some control. She followed them though they were heinous. Her mother's rules were horrible, but in her mother's twisted way, I think she was trying to protect Wavy. Her failing was that she couldn't even take care of herself and when she tried to keep her daughter safe, she ended up harming her. The rules robbed Wavy of her voice, her ability to eat, and made her feel dirty and unworthy of being touched. Her teachers were no better. They overlooked or excused her behavior. The only one who tried to understand her was Kellen, which is why in the end, she allowed him to touch her and see her eat. It wasn't until she started making her own rules that she could be free.