If you look at history you start to get the "evil" idea that Thanos was right. Every time the population is halved, or at least a significant part of it is eliminated, the standard of living of the survivors increases.
The Black Death (which was not bubonic plague, it was a hemorrhagic disease, which plague is not*) turned Europe from a continent where lords owned the people as slaves to one where workers had the power to demand improved standards of living and allowed for the creation, for the first time ever, of a middle class. Social mobility was created. Had millions of people not died and the social order of the world not been overturned those opportunities would never have arisen.
After 100 million people died in the Second World War America, as the only industrial nation that was not destroyed, saw the greatest boom economy in human history. For the first time ever a man with no education, no training, and no connections could demand, and get, a job that could support a wife, three kids, two cars, a house, a month of vacation, and retire in 30 years and live off a full pension. It was the first time ever that young adults could venture off on their own and not have to live in multi-generational families just to make ends meet (something still tragically seen as normal in our crippled economy). Had millions of people not died and nations not bombed to oblivion that opportunity would have never arisen.
Even in the Soviet Union, with that man-made catastrophe rent by Stalin that saw the murder of 20 million people, actually dramatically improved the lives of the survivors. An entire nation of peasant slaves was turned into an industrial super power with a standard of living half that of the United States in only 70 years. The survivors did have their lives improved. That would never have happened under the Tsar where everyone lived as chattel in an agrarian shithole.
History seems to attest to the fact that there really is a finite amount of resources, and if you eliminate half the people everyone not only gets double the share, but those double shares are worth even more.
"But why not just double the resources?"
Because things that are not earned have no value. Low IQ people take resources given to them by guilty Westerners and use those resources to quadruple their populations. Doubling the resources just exacerbates the problem by incentivizing bad behavior.
Everyone wanted silver, which was rare and highly valued. Wars were waged over silver. But when Spain discovered Potosi, the largest silver deposits in the world, and the supply of silver increased dramatically, all of a sudden silver became worthless because everyone had it and the Spanish economy collapsed.
Everyone wants to be a trillionaire, but when Zimbabwe made everyone a trillionaire the money became worthless. If everyone has a trillion dollars then no one will work, no one will pave roads, or build houses, or bake bread, or raise chickens. Why work when you're rich? But then, since no one is working, all those ordinary goods become extremely valuable and money becomes worthless.
Increasing the supply of a given resource devalues it. Increasing the supply of food, for example, would cause the excess food to rot and be wasted, or would incentivize people to have more kids who would demand more food, which would require resources to be doubled again to meet the new demand.
Any perceived increase in standard of living brought on by increasing resources is an illusion predicated on credit. Extraction of ground water and phosphate have allowed for an increase of food production which has allowed 6 billion extra people to be born in excess of the carrying capacity of the planet. The problem is ground water and phosphate take thousands, if not tens of thousands, of years to become replenished. Meanwhile they are exhausted in generations. Saudi Arabia totally depleted its ground water supply in a couple decades. There are places in America where the ground has subsided 70 feet or more because of the extraction of aquifers that took millennia to fill up. Whole "guano islands" were mined below the waves to extract phosphate for fertilizer and for making explosives and have been depleted in the past century.
It's a simple calculus: extraction of these resources allows for the increase of the population because most people have no concept of a future beyond their own death (or maybe the deaths of their children), an increase in population leads to an escalating pace of resource extraction beyond the point where those resources are being replenished, which leads to a population crash.
Now, it's true that places like Japan and Europe, especially Eastern Europe, have seen declining populations, but Africa's population is exploding. Within the next 50 years 1 in 3 people on the planet will be African if this trend continues. Sustainable agriculture can only support 2 billion people, and there will be at least 4 billion Africans who will not work, who will not invent new particle physics, who will not build rockets to colonize Mars. 4 billion more mouths to be fed by an increasingly smaller pool of Western workers who are being replaced in their home countries.
The long-term survival of the human species requires colonization of other planets. That cannot happen if dumb Westerners keep giving aid to countries in Africa and across the third world where people breed like crazy. There is a finite supply of resources, and those resources must be apportioned toward advancing the survival of the human species over the long-term, not increasing the population dramatically in the here and now.
The long-term survival of the human species requires the immediate end of foreign aid across the board.
“But wouldn't the population just grow back if half of it is eliminated?”
No, not if you eliminate the half that breeds beyond the replacement level.
You're committing the fallacy of assuming humans are fungible, like bacteria. If you eliminate half of a colony of bacteria the colony will just continue to grow until all the resources are consumed. If you double the resources for the colony to grow on the colony will continue to grow until all the resources are consumed.
If you double the resources on Earth some humans will continue to breed until all the resources are consumed. If you remove the half that is breeding beyond replacement level then those resources can be recycled, as they always have been.
Resources are recycled. There are water cycles, phosphate cycles, nitrogen cycles, carbon cycles. Humans use resources, die, and the dead bodies decompose and return the elements to the Earth to be reused. If population is kept stable, at the carrying capacity, then resources can be recycled endlessly. The world will not become overrun with Japanese people, ever. Japanese people are not exhausting resources to fuel their bottomless thirst for expansion, like in China or Saudi Arabia, or Chad. If the wasteful half is eliminated, or simply not allowed to expand, then the stable, sustainable half can reuse the world's resources endlessly until the Sun dies.
*The disease that killed most of the people in the Americas when the Spanish arrived is called "Cocoliztli". It has the same symptoms as the Black Death: high fever, profuse bleeding, large dark spots - especially around the neck and genitals, bloody diarrhea, bloody vomiting, severe body pains, delusions, discoloration and necrosis of the skin. Death was usually in 3-5 days after onset of symptoms, an extremely short amount of time. We don't know the incubation/latency period is, there are very few diseases that kill that quickly. People with Ebola usually linger for 21 days or so. Cholera can kill quicker, but that's from fluid loss.
Coupled with the fact that the disease is spread primarily from person to person, and was devastating in areas that were virtually rodent free while sparing other areas that were teaming with rats, indicates that some unknown viral hemorrhagic fever was the worst killer of humans of all time. It wiped out 75% of Eurasia and 90% of North and South America. We are all the survivors of some extremely virulent disease that nearly brought humanity to extinction within a span of 300 years.