Although you are certainly entitled to your belief that such concerns are fabricated, it seems pretty obvious to me that the threat of overpopulation in the next fifty years and resulting civil unrest, revolutions, etc are very real.
From the aforementioned NSSM-200:
"Whatever may be done to guard against interruptions of supply and to develop domestic alternatives, the U.S. economy will require large and increasing amounts of minerals from abroad, especially from less developed countries. That fact gives the U.S. enhanced interest in the political, economic, and social stability of the supplying countries. Wherever a lessening of population pressures through reduced birth rates can increase the prospects for such stability, population policy becomes relevant to resource supplies and to the economic interests of the United States."