It may not be there in actuality. It is from people's expectation. Hikers tend to love a nice, quiet, serene environment, and if a bicycle is coming down the trail, even safely, the hiker will perceive this s an infringement on their right to enjoy nature in its glory. The bicyclist, on the other hand, or many of them, come out here simply for recreation - to test themselves against the mountain. This is where people come to ride bikes.
Companies test their equipment out on our trails.
Biker's approach tends to be different, although many of them are environmentalists. So, there are bicyclists who understand resources and are interested in that. But I think the main conflict is 'why they are here' and their perceptions of what they are going to receive from being here. For hikers it's more observing nature and being at one with themselves, having a peaceful encounter with nature. And there's the horse riders, which is a whole other issue.