Well actually they did accept the surrender of the armies and forced the soldiers to take an oath. If they were US citizens why bother? They also forced the states to re-write thie constitutions which they had already acceptec prior to 1861. As a matter of fact I had read where Mississippi was one of the states that was refused admission to the Union after the war because of the way the new state constitution was drawn up. To me that acknowledges the existance of the Confederate States. It was only the government that was not surrendered.

GP