I think it is very weird that you compare less restrictive immigration policies to slavery. Slavery takes away people's freedom. Less restrictive immigration policies grant people more freedom than they already had. People can decide for themselves if they want to immigrate.
It is also weird how you call it racially segregated when it is possible for white Americans to immigrate to India and obtain an Indian citizenship and then have trouble going back to the US.
The closest thing we have to slavery is civil wars where prisoners of war are being forced on overloaded boats that are heading toward Europe. These people probably suffer from the same pain that African American slaves have suffered from but they are not slaves, they are refugees and rejecting them will just result in more suffering, not less. You can call this human importation but it was not initiated by the receiving nations which were actually tightening their borders.
It is also weird how you call it racially segregated when it is possible for white Americans to immigrate to India and obtain an Indian citizenship and then have trouble going back to the US.
The closest thing we have to slavery is civil wars where prisoners of war are being forced on overloaded boats that are heading toward Europe. These people probably suffer from the same pain that African American slaves have suffered from but they are not slaves, they are refugees and rejecting them will just result in more suffering, not less. You can call this human importation but it was not initiated by the receiving nations which were actually tightening their borders.