Let's see... it passed out of Lincoln-dominated Congress that was minus the seceded states. It was passed BEFORE the Confederation was ratified. Why did you ignore that?
Why didn't you check your timeline? The proposed 13th Amendment passed out of the House in February 28 and the Senate on March 2nd, both before Lincoln was inaugurated. If by 'confederation' you mean the confederacy, Davis had been inaugurated February 18 and the confederacy was operating under a provisional constitution which protected slavery and slave imports so the Amendment was passed AFTER the confederacy was established. So having protected slavery on their own why would the southern states suddenly call off their secession?