The concern was that they would thrive and progress, and soon demand control of their own natural resources. Meaning the West could no longer exploit their natural wealth.
There is a 1974 document briefing President Ford of this "problem" and he soon signed off on the "solution".
Good post. Is this related to Kissinger’s National Security Memorandum 200?
Most important post in this thread. Banning of DDT was pushed by the zero population growth crowd.