It is the case in the US (or has been since I was a child in the 80s) so I find the quote weird. You are supposed to walk opposite traffic for the reason described. It is standard guidance every I have lived (a large chunk of the US).
FWIW - growing up in Ontario, Canada I was always told to walk in the direction of traffic. It seemed odd to me to turn my back to danger, but that’s what they taught us.
In Finland it depends, with sidewalk and in populated areas the normal right side traffic is to be followed. At highways it is recommended to use left side specially during dark.
Yeah, in the US I learned walk/run opposing traffic, and ride your bike with traffic.
I learned to walk on the left as a child in the 1960s (from my mom and dad, who learned as children in the 1930s).
It's what I was taught in the US as well, if you're on foot you should be going opposite traffic