In your world governments forceably breed humans like chickens in massive factory farms churning out people to the carrying capacity of the planet. I don't want to live there and I sure as hell don't find it moral.
The whole point is that if you accept the fact that expanding population is good a priori, this leads to stupid conclusions by the tyranny of exponential growth. Who cares if the average person is a slave when you have several hundred billion of them. Who cares if mothers die horribly after being forced to carry child after child.
Personally I think the only consistent viewpoint is some form of logarithmic population * average well being metric to measure utility. From that perspective, I have no clue how a policy maker should act today. Hopefully smarter minds than mine figure it out!
Maybe if you're evil enough to not care about any individual human's quality of life. Is there a word for the logical fallacy where you argue against the most absurd possible interpretation of a person's beliefs in order to feel no guilt for disregarding them?
This is the standard issue with any aggregate utilitarianism theories of morality.
https://utilitarianism.net/population-ethics/
It's a stupid idea that's been soundly rejected because it posits arbitrarily bad living conditions since "anything" is better than nothing.