Ron - Of course we should all try to help other people, and I think it's disgusting the way the poorest immigrants are treated in the US.
                      But what I meant by my comment was this: some time after Teddy Roosevelt, people began to look around and discovered disappearing forests, dead spots in the oceans, endangered plants and wildlife, and they began to realize, too, that there was a limit to earths resources. Biological scientists and others recognized that more people put greater demands on resources.

                      Your right that the whole world is crowded, but a growing number of us are realizing that it doesn't have to be that way. Western Europe and North America had pretty much stopped their march to greater and greater populations, before migrants from other places began to arrive at those places which still provided a little breathing space.

                      The scenario would be different if the population went down each time an immigrant left his country of origin, but that isn't the way it works. People are moving from places that are already overpopulated to places that are not quite yet overpopulated.