I do not believe in this topic. Humans are not so many as we think. Even if we were so many, why reduce for what? Many people think that food will not be enough in the future but it is not true. We have a lot of places where we can cultivate. Countries like Canada and Russia are actually empty. People can easily move there if there are nowhere to go. With science, we can easily plant anywhere. We are already eating modified fruits and vegetables. We are doing great. We do not need to kill people or to reduce the population.
I completely agree with you. There are so many places in the world that are just empty. I would actually say that most of the world is not inhabited by people. People really just group together in the big cities. Of course, you wouldn't actually have to kill people to reduce the population. It can happen naturally. Nonetheless, I don't think it's necessary. In terms of food, people are worried that we'll run out. Well I've heard that we actually through out about 50% of food that is produced! If we just fixed that problem, we could feed twice as many people!