If they would pay the rent for renting land they don’t own there would be no problem. When you don’t pay rent you get evicted! Why should it be any different for them?
The government more or less “legally” owns anything they say they own at any time for any reason.
In this case they didn’t used to own the rights to it. Plus the family was willing to pay, just not to a corrupt organization.
http://www.freerepublic.com/focus/f-news/3143026/posts
What would the rancher say, if several other ranchers also attempted to graze cattle on “his” land? Other posters argue that the federal government is not the owner of the land. They may be right — I don’t know. However, neither does the rancher own the land. If no one “owns” the land, and no one controls who can graze on it, the land is effectively a “commons”. As in the cautionary tale taught to every first-year economics student: the “Tragedy of the Commons”. If there is no control over grazing rights, the land is soon destroyed for everyone.