Care to explain what that post means?
Historically countries that are living at the Malthusian limit have tended to either have despotic monarchies or devolve into competing warlord realms. In either case, slavery, serfdom, and a general lack of freedom have resulted. Examples include pre-1860 Japan, various periods in China, serfdom in Eastern Europe, historical periods in India, and many countries in Latin America.
The most free societies have been those with low population density, such as frontier America, Australia, New Zealand, Canada, and earlier colonies in Latin America and Africa where thin populations of agriculturalists took over lands formerly occupied by hunter-gatherers. Almost everywhere, freedom has declined as population density increased and competition for resources increased.