Reducing the limit of livestock permitted to graze under a new BLM grazing permit/contract is specifically permitted by the law.
You and I can disagree with the law in general. We can disagree with using that provision to limit grazing due to so-called habitats of so-called Endangered Species. We can disagree with using that provision if the government is euthanizing the same Endangered Species whose habitat the BLM used as the basis to limit grazing. We can cuss out the BLM in general and question the intelligence or abuse of power of those who in Congress and the BLM who made the rules.
However, the BLM's right to limit the number of livestock permitted to graze under the renewal of a grazing permit/lease is specifically provided for in the law. Change the subject if you want (again), but that what the law says, however ill-advised it may be.
And that is why lawyers make the big bucks. If law were as cut and dried as you claim Bundy would've been off of that property long ago.