Mountain Bikes on the CDT

Apparently the Continental Divide Trail has some of the same issues as the Pacific Crest Trail:

"Speaking of advocacy, thousands of acres in the Gallatin National Forest, including several epic sections on portions of the Continental Divide Trail, may soon be closed to mountain bikers. Forest managers are moving forward with a plan to designate the land as a wilderness area and off limits to bikes."

I found this snippet at Bicycling.com, where they seem hopeful that the area through the Gallatin National Forest will be designated a "National Protection Area," which would continue to allow bikes on the CDT. I am sure that there are some complex land use issues here (i.e. history, tradition), but I think the article is moot when it says: "[Patricia] Dowd added that an additional 1,300 miles of trails and roads were already open to bicyclists in the Gallatin."

What?  1,300-miles of trails and roads already open to cyclists?  Why can't cyclists be content with that amount of open trail? 

My hope is that the CDT follows similar rules as the Appalachian and Pacific Crest Trails and not allow mountain bikes on the trail. I am a cyclist myself here in San Francisco, and I recognize that there are some places where bikes do not belong like sidewalks, interstates and National Scenic Trails.