Why do people keep making excuses for children who kill in movies?

For example, Natasha Rimsky from Dark Water. There was no indication she had any murderous or sociopathic tendencies in life, nor was she preying on any of the other children while she was alive. The excuse that people give for her disgusting, repulsive, inexcusable actions is "she doesn't know how to control her emotions" or "she was traumatized", as if she was some animal at the mercy of her impulses. She could control the elevator, she could control water perfectly well. And she finally decided to let Ceci go when Dahlia finally gave her what she wanted. So don't give me that excuse of "she didn't know what she was doing". And she wasn't attempting to kill any children while she was alive. I wonder why is that?

Another thing I want to address is, why, if Natasha's just a snot-nosed, petulant scumbag, why didn't Dahlia develop any powers to contain Natasha? If I were Dahlia, I'd reject the little snot wishes, contain her rotten carcass with my powers and go and see and spend time with my daughter whenever and however the hell I want. No CHILD runs anything in my life or afterlife. Natasha is a CHILD. She isn't God Almighty.