Doesn't make much sense though when you compare it to reality. Most developed countries have a problem with low birth rates and their population is only maintained via immigration. And even the UN forecasts that human population with level out and start decreasing before the end of this century.

The elites rely on a large population of low class laborers to support their wealth as well and in the case of severe population decline they'll be quite vulnerable to all sorts of disruptions. It makes little sense to pursue as a policy as one gains nothing from it.

Too many people in the 60's and 70's bought into the population bomb nonsense but I suspect more than a legit belief in the idea that was thoroughly debunked, it is simply beneficial for a capitalistic system to promote short term gains over long term stability, so it behoves the people writing the checks to have workers that don't have "distractions" like family to take away from their productivity and superfluous spending habits, though even that is an extremely cynical take of the situation.

I expect the simplist explanation is often the best, humans are just retarded.