The BLM has been trying to get Bundy to keep his cattle off federal land for years. After 20 years of free grazing (he didn't pay $1M+ in grazing fees), they are finally removing them (and he will get them back).
Bundy argues his family has been grazing before the BLM was created, but the US existed, and the grazing land incorporated US territory. They are not taking his land away. They are protecting federal land. I don't see what the issue is here. The federal government employs principles of land use planning and environmental protection to preserve the natural resources and scenic beauty found on public land. A determination has been made and upheld by courts that this land is better off preserved than grazed upon.
Your facts are wrong. The fees claimed owed by the Bundys are in the range of about $50,000. When the BLM was created and given the power to charge existing grazing users, it was represented that these fees were necessary in order for the BLM to construct fences and improve waterholes/build ponds and troughs for the people who legally owned their grazing rights, according to many judicial results in our courts. Gradually, over many years the BLM has reduced it's expenditures for "improvements" and asserted charges for "grazing". We should never tolerate that kind of illegal actions by government officials. Grazing rights are real property interests, and the government is prohibited by the Constitution from enacting "Post Facto laws". . .. laws that apply to past facts. The government cannot change facts of law by passing new laws. New laws can't appropriate private property rights.
That's something the government, not even Congress nor the President has power to take without paying for those legal grazing rights.
The Louisiana Purchase was the first test of this principal. Thomas Jefferson understood the conflict posed by a Federal Purchase. But it was approved by Congress under the law that new states would be created, which would own the land in those states.
The State of Utah, on negotiating terms for Statehood, secured an agreement from Congress and the President, that all lands would belong to the State of Utah. Instead, only the lands covered under an old legislation regarding public support for schools within territories and states were turned over. Even so, the Federal government at that time was hold all federal land open for homesteading, and it went that way for thirty years. . .. before the BLM began to "manage" anything.
All legal precedent gives grazers or settlers title to their land. If you care to debate it, it can still be sustained on the legal principle of "Adverse Possession", the legal fact in the case of Cliven Bundy. If anyone settles land and occupies it for twenty years, it's just his, period.