You have decades, if not centuries of propaganda, that people need to have more children, that having as many children as you want is somehow a human right. Even recently in the past, there were yet vast undiscovered countries awaiting the world's population. The notion that one could have "too many children" and that this selfish behavior is intolerable will take time to catch on.

Even this thread is hopeful to me, a decade ago there wouldn't have been near as much disagreement about whether you have the right to burden society without limit.