The south had agreed to capitulate on that issue, Lincoln delayed meeting with the southern envoys to start the war. The goal was Federalism, slavery was the excuse.
Legal immigration is blocked in favor of illegal immigration, the goal is slavery, not immigration.
Proof you can have your cake and eat it too.
The speeches, articles, and official proclamations that attended Secession made it abundantly clear that the security of slavery in the South was the single compelling reason for Secession. After the Civil War was lost and its terrible cost apparent, the Lost Cause myth was developed by the defeated leaders of the South. This posited that issues other than slavery were the cause of the War. After all, when the cost of the War in blood and treasure was reckoned, the maintenance of slavery was seen as too small and ignoble a cause.