Even if what you say is true, its irrelevant. Its the government's land. They can use it for any legal purpose. They don't have to get this guy's consent to use their own land as they see fit.
It is not that simple as it seems. Bundy's family were the first European Americans to ever settle on that land, after defeating the Shoshone. The government used the services of that family to defeat the Indians. And in return, they were granted grazing rights to the whole area. How can the government take away something that was granted many years ago?