The problem is that there's just far to many humans.
Yes, I cannot agree more, but a "purge" is definitely an extreme point to which I don't think it would be healthy to go. As a species, we have the intelligence and agency to be critical and discriminatory when it comes to our reproduction, and if everyone can just control themselves from farting out babies and polluting the earth, then the population will eventually come under control. We have the knowledge and systems to produce large amounts of food and water, but our population is so massive that hundreds of millions of people are malnourished. There is not enough. And many of those who DO remain fed well do so only at the cost of bleeding their lives away at painful, unfulfilling, soul-destroying occupations. The truly happy person has been made an endangered species. Air, for example, is something you need to consume to survive, but costs no money. The reason for this is clear, it's because no-one can monetize or control the distribution of oxygen as it's literally everywhere and immediately accessible. The same can be true for food and water. The population can decrease to the point where food and water amounts number in high excess of the demands of the human population, making it free and plentiful. Not to mention the kind of biological beauty that could develop if developed land were to be allowed to return to a healthy, fertile state, which is actually more difficult and time consuming than it seems, as our rampant use of chemicals like herbicides and pesticides has taken a toll on the quality of the soil and
water.
Not only that, but we can drastically further our species' evolution by simulating the process of natural selection, only by now using intelligent selection. If people really thought critically about whether or not their genetics being in the next generation would serve to elevate the human race as a species or not when they have the impulse to reproduce, instead of their current, selfish, myopic questions like "are we ready to be parents?", then we can elevate the state of humanity at a unprecedented rate when compared with the randomness in Darwinian evolution. But of course, stupid people are social creatures, and they won't do the right thing unless someone is there to scorn them for it, it seems. Unless it becomes socially stigmatized (just my theory) to have kids in a world this overpopulated, people will not control themselves. If you look at the world now, it's even universally CELEBRATED to have children, with thinks like cards, balloons, and baby showers.