It's a variation on monument veneration.
A while ago, the National Parks put up an observation tower at the Gettysburg battlefield so that tourists could get a panoramic view of the ebb and flow of the battle. Purists were outraged. They believed the mere existence of the tower sullied the pure essence of the battlefield.
The problem some environmentalists have with the overlook is the same phenomenon, only with nature instead of history. It's not opposition to human activity; it's opposition to change.