Urbanization and deliberate rural depopulation are not the same thing. Besides, why is it a silly attribution when it's the written policy of well established American leftists? The Global Biodiversity Assessment specifically names the The Wildlands Project as key to its implementing strategy in North America.
The Wildlands Project is a "land conservation strategy" developed by Dr. Reed F. Noss under contract with the National Audubon Society and The Nature Conservancy:
"I suggest that at least half of the land area of the 48 conterminous states should be encompassed in core reserves and inner corridor zones (essentially extensions of core reserves) within the next few decades.... Nonetheless, half of a region in wilderness is a reasonable guess of what it will take to restore viable populations of large carnivores and natural disturbance regimes, assuming that most of the other 50 percent is managed intelligently as buffer zone. Eventually, a wilderness network would dominate a region...with human habitations being the islands."Source: Reed F. Noss, "The Wildlands Project," Wild Earth, Special Issue, 1992, p. 21.