Nectar,
While public lands might not be a top tier issue for some, they matter beyond what it gives us for recreational opportunities. In the west, for example, our water supplies and our irrigation water start on public lands. Healthy watersheds means healthy people and healthy crops.
Public lands provide low cost grazing options for ranchers and can be managed in a sustainable fashion.
Public lands help fill the United States treasury through energy production (coal, oil, natural gas, uranium).
Public lands are economic drivers in areas where there are large blocks, and protective designations like National Monuments have been proven to be revenue generators. Public lands help diversify local economies if managed in a sustainable fashion, and help create more jobs than if the land was privately held.