With respect, Carl Jung notwithstanding, KC is responsible for KC.
Many of us came from homes far worse than KCs, and still managed to grow into responsible, caring people. It's all about working to get past one's family of origin, and deciding what kind of person to be.
If you believe that we are karmically put into a situation of optimum learning, at birth, you believe that KC was, as well. Then, KC's karmic lesson may have been the challenge of growing into responsible adulthood. Clearly, she chose to avoid the growth and flee the lesson. Her choice.
Collapsing into a, "my Mom made me what I am," mode stunts personal growth and is a moral and emotional cop-out. It amounts to a refusal to grow up. Most therapists do not encourage patients to persist in that mode of thinking.
KC knew what she was doing, that it was illegal, that society held it to be wrong, and that she would be punished if caught. Her choice, her consequences, her lesson.
KC could have got a job (or stayed with the one she had) got a place to live, got some counseling, and learned to interact wih her family constructively (or not at all) llike many of the rest of us did.
Cindy may be lousy Mom. Many of us have had bad parents-- even brutal parents. But, Cindy did not kill the baby. KC killed the baby.