I suspect this story says more about how "the system" treats minors whose parents become incapacitated then it does about how the U.S. treats foreign guests. It does raise an interesting question, however. Do parents, particularly those traveling alone with their children, plan for their care in the event they become hospitalized or worse? I doubt that my parents did when I traveled with them as a child but, evidently, very unpleasant things can happen to children who find themselves deprived of access to their parents in a strange city. Even if a parent has travel insurance that will pay for a relative to come get them, what happens to the kids while they wait hours or even a day or so? And, of course, the relative would need some kind of pre-executed authorization to remove the kids from the country, wouldn't they?
I'm sure, with some careful pre-planning, this kind of situation can be dealt with so kids don't suddenly find themselves treated like indigent orphans by the social service system, but I'll bet most parents don't consider the possibility when they travel -- mine certainly didn't. Sounds like a cautionary tale for parents: "hope for the best, but plan for the worst."