Why does Cordelia end up effectively punished for her father's mistakes?

The good daughter, Cordelia refuses to insincerely flatter her father with false estimations of love and is disinherited. France marries her and she becomes Queen. We hear of her knowledge of Lear's mistreatment and her movement to Dover with the French army through Kent. She takes Lear to a doctor to treat his madness. She and Lear are captured by Edmund when the French lose the war. Lear hopes to spend quality time with her, but she is hanged by Edmund before Albany can send help. Lear carries her body into the final scene and dies with her in his arms.