My dad and uncles all fought in WW2. The uncles lived in a small farm town in Southern Illinois, and all shot guns regularly. My dad grew up in Chicago, and even he had handled guns and shot before the war. (He really liked a WW1 Luger he shot before the war).
The US was different 70-80 years ago. At that time, a majority of the population still lived in rural areas and small towns, not in large urban areas. Urban growth and the explosion of suburbs did not explode until post WW2 (1950 to 1960)