As I understand it, part of the 'road' is on an easement obtained from other property owners. It is quite common when an easement is granted that the landowners require certain fixtures - like fences - to keep the easement (in this case a road) from being a hazard to their livestock or wildlife. Also a fence reduces the potential liability of the landowners from third party lawsuits such as a driver suing them for tumbleweeds that caused an accident and the lawsuit claims the property owner had a duty to protect drivers from tumbleweeds from their property.
It can often be a zoning requirement as well by government.
So building the fence is almost certainly just a legal requirement that JACK HANKS had to agree provide to the landowners in order to get the easement to bulldoze the 'road' or to comply with land use legal requirements.