I don't know if you can can say the entire USA has an "obsession" with preventing children from being autonomous based on this one incident. That's too much of a generalization. There are obviously people who do think that way. But there are also a lot who do not, including the mother, who said "I was not panicking as I know the roads and know he is mature enough to walk there without incident."

This situation is ridiculous, of course. But the USA is huge, and you can probably find pretty much any or every attitude and approach to life here.