The world can sustain the current number of people many times over in terms of food supply. Indeed based on sustainable (vegetarian/vegan) food.

Talking about how many people can be sustained by earth is talking about the wrong thing. It only leads and HAS only lead to the eugenetics part. Because it's always poor people in different countries who gets sterilised.

The real topic is that capitalism and consumerism is 100% unsustainable, right from the start. That is the real debate to be had. That this world is not about human well-being and happyness, but about GDP and growth, making a tiny number of people wealthy at the expense and misery of the majority.

Unfortunately this site - Hacker News - and everything related to it, Ycombinator, Paul Graham, is only fueling the capitalist game.

I still don't see how my comment specifically relating to reductions in the birth rate in the US (a rich country) perhaps becoming a trend for all humans is remotely similar to sterilizing poor people in different countries.

> and gradually find equilibrium at a more sustainable population.

You talk about "sustainable population", there's nothing not to understand about this. Sustainable implies it's now unsustainable, but that notion isn't true.

If we must all become vegeterian/vegan then to me that proves that the planet is currently overpopulated. In my view a sustainable population level is one that does not require drastic measures because ultimately we want the best quality of life we can have and not live like in a dystopian movie.

Going vegetarian/vegan is about the environment, not about the number of people. Even with half of the world population, meat-based diets are unsustainable.

Why do people insist on making this an eugenics talking point?

The number of people is not the problem.