They are trying to encourage more dispearsed camping. The first place people look for a camp is close to water. So all the existing camps spots from a century of use are near the bodies of water. When people select a camp site. They want to be close to water so they don't have to haul water any farther than they have to. Also most basins collect water in the bottom of the basin. Which is usually the flatest area. the mountains around a basin are usually much steeper, So campers naturally gravitate to the Easier Camps.
The Forest Service efforts here are to encourge folks to not camp in the highly popular areas and to dispearse into a wider area. So instead of having tent in the same place EVERY weekend, The camp site may be on the East side this week and the west side next week etc.
The hot wire is just the rangers interpretation of what consitutes a STRUCTURE. Since the way the regulation is written, they Forest Service has tried to make it Broad enough to cover any type of camp. ie Structure includes, Tents, Lean To, and in our case a corral.
The forest service is also trying to prevent campers from consuming all the wood around popular camp areas. They feel that in heavily used areas campers have picked up all the dead wood and even killed live trees as they try to collect firewood. They feelthat wild creatures need the wood. It provides homes for insect that live in or feed on the decaying dead wood. Squirrels and birds live in and around brush piles. etc.
This is public land. Meaning that all americans can access the land, but the Forest Service has the duty to manage the land. In the old days, nobody seemed to care. But as the population has grown, camping has become more popular, The forest service has become more restrictive in how it manages the land.