I tend to agree with you philosophically, but when it comes to implementation that's where I really struggle. How do you curtail either of the two types of growth? It seems like the only options include authoritarian and borderline human rights violating. A group of progressive countries could band together and try to invade China and force them to slow their growth, but even ignoring the ethicality of forcing our will on others, most people would agree that the death and suffering would be pretty bad.

So far the best form of population control has been prosperity. Birth rates tend to fall as quality of life goes up (not always of course because there are many factors in that). The other option is outlawing reproduction much like China did for a long time. That seems questionable re: human rights also.