Well, I think it's meant to discourage permanent immigration and also protect jobs which are in short supply. The worse you make conditions for immigration the fewer immigrants you have.
As population density increases, it's only natural that countries want to reduce population. Between telling people to not have children and preventing immigrants from entering, politically it's more palatable to stop immigration.
As population density increases, it's only natural that countries want to reduce population. Between telling people to not have children and preventing immigrants from entering, politically it's more palatable to stop immigration.