Do I feel bad for KC because of how she was brought up? YES I DO. But, I would not let those feelings come in the way of what I must do to protect myself from her.
IMO, and based on my experiences in my own life, CA is a Borderline-type mother who has raised both her children (and her husband) in a toxic household. ICA is the product of her mother and her environment, along with whatever happened to her at birth/in the womb, etc., that resulted in her developing into a sociopath.
Both CA and ICA are like an alien species to us -- they react in an alien way to events in their lives, and they are consumed by a basic "survival at all costs" instinct that allows them to lie, cheat and steal when their "survival" is threatened. My husband's ex-wife is like this, and my stepdaughter has turned into a "mini-me" of her mother. They have a love/hate, co-depependent, enmeshed relationship. They scream, yell and fight with each other -- but will defend each other to death if any kind of outside entity tries to "attack" one of them. I believe CA and ICA are like this. The DT will try to keep ICA away from her parents, but she will be unable to stay away from her mother as she is too enmeshed to separate-- unless she undergoes years of therapy. CA loved Caylee because she was like ICA was ICA she grew up and could voice her own opinions, defend herself and try to separate from her mother. This, IMO, is why Caylee was killed -- to ICA it was the ultimate "fu&#-you and a way to finally sever the chord that existed between her and her mother. JMHO
More to add -- I don't believe that CA understood how dangerous ICA was until she realized what ICA had done to Caylee. ICA had taken the dysfunction as far as it could go, resulting in Caylee's death. This is where CA and ICA differ.