It is already politically charged to deal with such issues as oil depletion and climate change but, at least, these are physical problems that we can examine using the scientific method. But overpopulation? That's the recipe for an instant politicized or religious quarrel.
The movie "Population Boom" by Werner Boote is a good example of how politicized and emotional the population question can become. It starts almost immediately with a potshot at the Reverend Malthus, accused to "have predicted a catastrophe for 1860" (something that poor Malthus never said.). Then, it goes on for one hour and a half in the attempt to demonstrate that there is no such a thing as an "overpopulation problem." Rather, the film's thesis is that the world is seeing a conspiracy by the elites of the rich countries who are trying to stop the people in poor countries from having as many children as they want so that they could become rich, too, and challenge the world dominance of the present elites.
If we accept the idea that all opinions are legitimate, then also this one should be - even though probably a bit too extreme for most of us. The problem is that the way the film tries to demonstrate its thesis oscillates between the boring and the silly; without ever providing a serious argument. Mainly, we see the filmmaker, Mr. Werner Boote, walking around while carrying his umbrella in places where it never seems to rain. In his ramblings, Mr. Boote interviews people who, frankly, don't seem to have a clue about overpopulation, except for seeing it as an invention of the evil Western Elites (and the same is true for global warming, explicitly defined as such in one of the interviews).
Most of the arguments made in these interviews are so silly that they are not even worth deconstructing. Just as an example, in a scene we see Mr. Boote (for once without his umbrella) discussing with a man who tells him that Africa is not overpopulated because it has only 40 inhabitants per square km, compared with the 170 of Europe. Then, the man takes Boote somewhere and he shows him an empty landscape, saying, "do you see? Africa is not overpopulated!"
Now, there are several problems here. The datum for the population density in Africa seems to be correct, but the population density in Europe is 105 inhabitants per square km, not 170 (and it is just 31 if one includes Russia.). Maybe Mr. Boote's informant meant Western Europe, but if you take that as meaning the European Union, then the population density still is only 116. Then, one would be tempted to remind to Mr. Boote's informant that Europe doesn't have a Sahara desert; to say nothing about the Kalahari desert and other areas unsuitable for human occupation in Africa. So, he conveniently forgets that an African country such as Nigeria has about the same density of population as Switzerland (nearly 200 people per square km), to say nothing about Rwanda, that has 460 people per square km (more than twice than Switzerland). Finally, one could show to Mr. Boote and to his informant the Yosemite valley or the Death Valley and then tell them: "you see? Almost no one lives in California!
I could go on, but I think this is enough for this movie. Let me just add that if you think that the poor do not pollute the ecosystem, you would do well reading this post by Jacopo Simonetta.