I suspect that the real battle is not over the 23 cows in the park, but rather an attempt to circumvent the grazing rights of the rancher in such close proximity to the park. The battle over grazing rights has been rather robust in the Idaho, so much so, that the motorcycle folks, four wheeler folks, and horse folks (at least to to some degree) have been working together to keep the land open for multiuse. Essentially, anything that may disturb the ground has been seen as the enemy. Even hikers are not immune from this battle.
Unfortunately, not all of the multiuse groups are agreeable, and some, especially some cattle grazers, think that they are immune from litigation because they raise one of God's creatures. This incident is indicative of a larger scale fight that many would not like to admit. The rancher will probably lose, or go bankrupt trying to fight the deep pockets of the government.
If all PUBLIC land users would realize the true meaning of multiuse, we would have one group fighting restrictive use instead of a host of small groups who are generally under funded. I suspect that our succes in avoiding land closures would be much more frequent.
Rick