Sorry, but that's a lot of hyperbole.

In the example posted, grown adults left their minor children alone on a ski hill for 7 hours straight, the kids ignored a sign both could provably read that said to stay off the excess hill of snow that was by the lodge, and the kids went and played on it anyway. One fell, and broke her arm. No ski hill can personally supervise every last person on their hill, and while the general onus for care is on the operators, part of the onus for care of minor children is on those parents. They don't magically absolve themselves of responsibility for their progeny because they walk into a private business.

This kind of culpability splitting simply reflects reality, where few situations are firmly black and white, and many have multiple contributing factors.