They call them the bad lands, because the land is no good for planting and cannot harvest anything.
That's also why it is preserved the way it is and it feels like no time passed by ever.
To me there's nothing Bad about the badlands, only beauty.
The area photographed in this documentary is owned by a family for many generations. This family just loved their ground, it was their home and they didn't feel any need to change it or turn it into a public park or other touristic kind of place at the time of photographing.
But well, as times are changing, later on this area also got it's vacation cabins and a purpose to be an part of giving an income.