As an urbanherder, or someone that actively works around sheep I certainly understand the ranchers need to protect their sheep, but as a rather avid mountain biker I sure as hell don’t want to be attacked by dogs or any other animal for that matter.
My experiences also lead me to believe that mountain bikers are at least somewhat at fault here as well. Great Pyrenees, the breed that generally guard sheep are not, in my experience, aggressive unless you mess with their sheep. If you are dumb enough to engage the sheep you should expect trouble from the dogs.
Either way, this story makes it sound like both the ranchers and the cyclists are taking precautions which is a real good sign. When either side, or both, are intractable nothing gets done.