A few reasons first of which was because it was a terrible way to treat other children of God.
Robert Morgan, a writer for the Institute for Historical Review, confirmed that, on Aug. 14, 1862, Lincoln invited free Black ministers to the White House to have a conversation. Lincoln did not hesitate to convince them of their inferiority when he candidly said the following: “You and we are different races. We have between us a broader difference than exists between almost any other two races. Whether it is right or wrong I need not discuss, but this physical difference is a great disadvantage to us both, as I think your race suffers very greatly, many of them, by living among us, while ours suffers from your presence. In a word, we suffer on each side. If this is admitted, it affords a reason at least why we should be separated.”