Zoning Laws, Immigration Restrictions, and a Leftist Defense of Abortion
An open borders policy will not eliminate the ability of people to restrict who moves in. It will simply eliminate the ability of the non-affluent to do so. The affluent can keep out undesirables by fiddling with zoning laws or building codes. In an emergency, they can raise tax rates to the point that their neighborhood is unaffordable.
When the above argument is used to defend immigration restrictions, it is analogous to a common pro-abortion argument.
By the way, if an anti-abortion law raised the birth rates of the rich more than the birth rates of the poor, we would hear how it's racist. Wouldn't that mean that an anti-abortion law that raises the birth rates of the poor more than the birth rates of the rich is anti-racist?