That's true. Lincoln laid the groundwork for the continuation of slavery after the war, though he did it because he believed it necessary to prevent widespread murder and crime in the south. In any case, Thaddeus Stevens saw to it that Americans of African heritage were freed by federal law despite Lincoln's comparatively sophisticated gambit. Sadly though, Thaddeus died before he could rule the south long enough with an iron fist to prevent the savage genocide of Americans of African heritage that followed his death.
The 13th Amendment had nothing to do with it, huh?