Why didnt the south want slaves

The War between the States was fought for many reasons, not just slavery... but anyway, moving on:

The South wanted slavery because it made up a fairly large part of the economy; at least, the rich, politically important big planters preferred using slave labor, because it was really cheap once one invested the money in purchasing slaves. Once those big planters were using slaves and were getting rich off of it when the cotton gin was invented, it got entrenched deeply into the South.

As to the north, they really didn't care about slavery. There were abolitionists, yes, but they were regarded as crazy folk, generally. The average Northerner didn't so much care about the fact that slaves were being held, they were concerned however that free black people would be forced to go up from the relatively jobless South into the factories of the North, where they would undercut wages. Thus, while the average Northerner might not have liked the situation down South, they weren't for abolition, either, since that would slash their already meager wages even more.

By the way, an interesting tidbit; in the South, people said that it was the North that was morally corrupt for this; a slaveowner, they said, was at least obligated to make sure the slaves were fed, clothed, and housed well enough so that they could keep on working. They said that this was better than the North, where the business owners didn't care enough to give people wages they could live on; after all, if you lost an arm in their machines, what did it matter to them? They could hire some other shmuck fresh off the boat to work in your place, and they'd probably work for even less.

Now, of course, we look at it differently.