One of the big drivers of population growth is being a poor farmer and preserving a legacy. Once you have some wealth, the incentives change.
My grandparents grew up poor in rural Ireland, my grandmother was one of 12 children and at least 16 pregnancies, born in the WWI era. 9 of the siblings made it to adulthood. They needed people to milk cows and catch fish, and needed living sons to inherit the land and take care of the elders.
Immigration in modern western countries fills the gap between productivity gains and the dearth of workers. It keeps salaries lower to reduce inflation and preserves the status quo. Remember that behind of all of these crazy debates is a need for certain stakeholders to maintain power.
That doesn’t seem correct. Waves of Hispanic and Asian immigration has reshaped California from Conservative to _the_ most liberal state. CA also has high minimum wages and much better worker protections than most other states, due to the liberal leaning politicians that got elected.
Why do you think that these folks are so upset about immigration from Latin America and Asia? The old way was to exploit cheap immigrant labor... but after many years, you now have a situation where that immigrant labor is disrupting the status quo.
This has happened before. The same type language directed at Mexican and central american laborers was directed at Irish, Italian, Greek, Chinese and Jewish immigrants in the 19th century. Race, religion, supposed immorality, the same shit. See the Page Act, Chinese Exclusion Act and "Know Nothing Party".