Extreme ideas like capping populations at a fixed number and further dividing people arbitrarily due to weird rules, people who have the same culture and language and identify as the same people but have different statuses and lifestyles due to their current governing body … This all requires really strong authoritarianism, and a crackdown on human rights to control the growth of the population and a strong military to keep borders in check.

It would fucking suck. It just means more borders, less places you’re allowed to be, stronger military police forces to enforce these things, and people getting in trouble for being pregnant or having too many kids or hopping a border to live with family they got separated from.