All of you saying that the movie went out of its way to victimize Aileen
Regardless of what you think of her, she was the victim in some sense here. Is she still accountable for her actions? Of course. Did she deserve to die? Probably. But she was victimized too, just as am i'm sure many other children are too. But the abuse she endured, coupled with the fact that she most likely had a predisposition to her violence (her being a sociopath) made her into what she was. Of course she was a crazy bitch, of course you'de probably want to *beep* kill her if you had to deal with her, but that doesn't change the fact that she's a pretty tragic figure, as are most people in this situation. Do you have to feel bad for her? No, but that doesn't change the fact that she was a victim in that she never had a chance, which she obviously never did.
This is a pretty weak example, i guess, but one of my old friends is a very bossy, selfish person most of the time. She's greedy and outspoken and looks out for herself. As much as i don't want to be around of her because of this, and as much as i find her irritating, i understand why she is the way she is, and that's because she's had a very bad childhood. Her mother would often throw her out on the street from before she was even ten years old, and she'd have to find a place to stay, food, etc., so this basically explains why she feels the need to be that way.
If you don't like seeing these kinds of things happen, don't watch the movie. This is reality for a lot of people out there. I'm not just talking about abuse or about serial killers, but if you pay attention, it shows you all the factors that go into making Aileen and people like her what they are.
Plus, the acting was phenonmenal :D