I’ve seen little children take the subway alone in Japan. Its a completely different environment
And yet we are constantly bombarded with fearmongering around children getting kidnapped on every street corner, every hour of the day.
I'll absolutely agree that a place like Tokyo is safer for a child on their own than NYC or SF, but the gap isn't as wide as the mainstream media would seem to suggest.
By far the most dangerous thing for kids, is traffic. And in many places that is the delimiter of their freedom.