Did I say otherwise?
This seems to imply that regardless of what you teach them they will do what they want:
I suppose you could say that she should have been taught not to behave that way, but, as I am learning as a parent, sometimes it does not matter in the slightest what you try to impart to your child, they will do as they do.
Whereas in this case she's not even trying. Parenting is about teaching and guiding, not giving up on crazy children.
I used to throw my cat when I was a kid. One day my brothers threw me back and forth and I never threw a cat after that. I was about 5 years old and I still vividly remember that lesson. Kids learn, you just have to keep trying.
If you have a kid that's touching other children inappropriately you don't say "Welp, fuck it. There's nothing I can do, I'll just raise a potential pedophile."
The problem with this story is not that Lena wasn't getting the lesson, it's that the mother was not even bothering to teach boundaries.