If a bank leaves its vault open to the street and unguarded, it's possible for the the thief and the bank to be simultaneously and fully in the wrong, without the negligence of the bank being somehow compensated for or compensating for the guilt of the thief.
We don't expect children to be perfect; in fact, we expect that they need to make mistakes to learn from.
The bank in your example is beyond negligent, as it provided the opportunistic thief the opportunity to abscond with customers' money the bank exists to protect.
In this case, the bank is the parents of children who are obligated to supervise their behavior online, not the children themselves.
I'm a parent and I'm not sure why the idea that parents should protect their children is somehow controversial.
In this case it should not be necessary - the world should be a better place, without these sick assholes preying on children. However it is not a better place and so parents need to be aware.
