See, the USA has 350 million people, and fifty states with materially different local norms. With this scale and amount of variety, "one in a million" freak incidents ought to be registered all the time. But, being freak incidents, they get amplified and thus seem to represent the entire country in the eyes of distant observers, foreigners, or just people from far enough away within the US.
Ironically, this is the same mechanism that magnifies every freak incident in daily life and gives it disproportionate news coverage. It's sometimes useful to draw attention to a rare problem, but more often it's just to pump up the audience's emotions and thus drive up "engagement" (views, coincident ad impressions, contextual ad clicks). This magnification, if not dampened by some rational thought, leads to people, including officials, mortally afraid that "anything could happen" with an unattended child on the street, and over-reacting; jail time for a parent is definitely worse for a kid that walking alone on the streets for some time.
But again, talking about "the USA lifestyle" is about as productive as speaking about "the European cuisine". The lifestyle is highly varied; I myself is not a fan of transactional suburban SUV lifestyle, hence mine, and that of my neighbors, is vastly different.