The message being sent by those who rant and rave about overpopulation is a demonization of humans, plain and simple. The message seems to boil down to "humans are parasites on the planet". To put it in the most plain and witty language: if you think there are too many humans, you can start off by commiting suicide. Then the rest of us "greedy" humans who actually do value life can continue on our merry way without having to worry about others advocating killing us through population control.
To begin with, most 1st world countries are actually underpopulated - there are vast stretches of unused land and resources, especially in America. Drive through the Midwest and tell me how overpopulated it is. There is a lot of livable land that is unused. The entire world's population can fit into Texas with the density less than that of San Francisco. Europe is currently shrinking in population even with immigration and will continue to shrink.
Any population is optimal to the extent that the economic system can sustain it. Free market capitalism is by far the best system for such a task. Countries that are deemed as overpopulated don't face a problem of too much people so much as the lack of an economic system to adequately sustain living standards for that quantity of people. The solution is not to therefore make there be less people. The solution is to improve technology and the economic system so that such a quantity of people can be sustained.
The bar of population is raised with improvements in technology, and improvements in technology are brought about through production and the accumulation of capital. Before the industrial revolution, the world population could only be sustained at a much lesser rate. It was the improvement of economic conditions and creation of technology, which resulted as a consequence of the rise of free market activity, that raised the bar that allowed us to have a larger population in the first place. Anyone who actually values humanity in any way should prefer improvement of the human condition, not annialating humans.
Some neo-luddites/radical-environmentalists would like to abolish industrial activity. Of course, this is another way of supporting population control. It would be to go after the very thing that raises the population bar: technology and the accumulation of capital. If taken to its full implications, it would constitute a massive loss of life around the world, especially in 3rd world countries. Proponents of population control should always remember that it is precisely the less fortunate who will be first affected; I.E. they are advocating 3rd world genocide, in effect.
No, sorry. I'm more concerned about improving people's living conditions than reducing the amount of people. The amount of people is optimal to me so long as it is sustained and within the context of voluntarism. Overpopulation fear can only lead to two ultimate conclusions: people other than yourself should be put to death, or you should kill yourself. The first option is always selfish because the advocate of population control never offers themselves, but asks that others die to calm their fears (and it may very well be coupled with alterior motives such as getting rid of a particular class or race of people). At least be consistant and kill yourself.
Mankind's biggest problem isn't the existance of people! It's the use of aggression against the person and property of others that has always been the bane of mankind. In either case, if overpopulation is really your concern, I have a suggestion: it's a self-correcting issue, because once the population goes over the bar, some people are going to die anyways. So all you have to do is wait it out, and good old social darwinism will work things out. There is no need to advocate any policy at all to deal with overpopulation. Overpopulation naturally cures itself, as the exess population starts to die out naturally.
But some of us are more humanist than this, and we'd prefer to continue raising the bar rather than just sit back and watch people die. You're welcome to join us in this grand project we call civilization. If you want to improve the living conditions of people and make a higher population sustainable, it would be wise to support the main thing that brings this about: production. The idea that we should ensure the future of the "planet", but not the future of our species, and the idea that the best way to ensure the future of the planet is to decrease the amount of people, is nonsensical. "The planet" will be here for a long time. Humans present no threat to it, and the notion of sacrificing humanity in the name of "the planet" is a joke.
Consider the simple ethical implications of population control. If someone kills another human being, most people would aknowledge that this is in the wrong. Yet population control is the same thing, accept as a government policy and on a massive scale. There is a wide difference between social darwinism and population control. Social darwinism, while it certainly has flaws as a social theory, is people naturally dieing due to natural selection.
Population control is deliberate, not natural - it is the purposeful lowering of the population (wether through direct murder or denial of access to resources), in resistance to natural selection. Those people who would have stayed alive through natural selection are killed off along with those who would have not. Of course, modern offensive wars count as population control by all accounts, and restrictions on immigration are also population control in many ways, so there already is a degree of population control policy in western politics.
There are some interesting potential paradoxes in relation to population control and the political agendas of both the right and left. The right tends to put itself foreward as defenders of life, as bitter opponents of population reduction. Yet this is entirely inconsistant with their simultaneous tendency to support war, which deliberately destroys life, and their xenophobia with respect to immigration. They also, ironically, might tend to support cutting funding for programs that may artificially keep certain people alive (of course, they are correct in opposing welfare).
The left has its share of contradictions in this matter too. On one hand, the left contains the bulk or majority of people complaining about "overpopulation". Simultaneously, leftists tend to put themselves foreward as bitter opponents of war, they are in favor of subsidizing immigration and they are dedicated wholeheartedly to the continuation and expansion of welfare. If the leftist truly is concerned about overpopulation, in order to be consistant they would have to support war, restrictions on immigration and cutting of social programs.
Of course, to put things in perspective, some of these positions of both the left and right are good, and others are bad (to be clear about my position: war = bad, welfare = bad, immigration prohibition = bad). The point, however, is to demonstrate a certain inconsistancy with respect to how their rhetoric compares to what policies they support. It seems odd that those who claim to be the most pro-life have a tendency to support war and protectionism. It also seems odd that those who claim that we have an overpopulation problem would simultaneously put themselves foreward as opposing those policies that destroy life (not that Democrats have ever been reliable as anti-war canidates, nor that Republicans have ever been reliable as free market capitalists).
The overall point here is that both the contemporary right and left are prone to overpopulation hysteria and support population control, although in perhaps somewhat different ways. Both are prone to advocate that those groups which they don't like be subjected to population control. While the contemporary rightist does not have any misgivings about killing people abroad, the contemporary leftist does not have any misgivings about the complications of abortion or killing those who do not adhere to economic decrees. Both sides will find ways to try to "justify" population control on certain groups. But let us stop using this rhetorical obfuscation and call a spade a spade: murder, murder, murder.
The first ethic that any civilization learns is that murder is wrong. Unfortunately, many people seem to advocate what amounts to murder in the name of political ends (wether that be "defeating the terrorist enemy" or "achieving equality for all"). If you think that less people should exist, particulrly directed at humanity as a whole, then the only consistant thing for one to do is advocate or engage in murder of them (additional suggestion besides suicide: become celibate). The rest of us who aren't criminally insane will continue to oppose such violent activity, and we will continue to produce more human beings, no matter how many people are killed in the name of unrealistic ideas.