For amusement only. This is simply a philosophical exercise to help clarify values. Everyone and every living thing on this planet will benefit from an improved human population density. The promise of abundant living will once again be more than wishful thinking. Shortages of resources are caused by longages of consumers, so the fewer we number, the greater our material wealth could be.
Social justice demands a more equal opportunity to exploit Earth's resources.
A dubious goal, more easily achieved when there are fewer people to re-distribute resources to. Children will be more respected and better cared for as there are fewer of them. The appalling numbers of children dying today could be reduced to an ugly page in the history books. Housing will become plentiful without building more houses. A sustainable civilization will be possible when we stop taking more than is being regenerated by Nature.