Your public school indoctrination was successful. Also, your statement appears to be internally inconsistent. If the North didn't go to war to free the slaves, then why would the South need to do anything to preserve slavery?
I went to Catholic schools bozo. You going to knock Catholicism? Go ahead, I dare you. The North went to war to preserve the Union because the South seceded in order to preserve an economic system based on the use of slave labor. It started a war to preserve that system and lost. The South lost the war it started and no amount of historical revisionism and intellectual acrobatics by you Lost Causers is going to change that fact.