I explained the difference to you earlier in post 25.
Recall, slavery was Constitutional, so one cannot condemn them for defending their Constitutional rights
The Confederacy did not secede because the federal government threatened their legal privilege of owning slaves. President-elect Lincoln was very clear on this point.
The Confederacy seceded because the South no longer had enough seats in Congress to prevent a Congressional majority from refusing to admit any new slave states.
Some people say that the Civil War was not about slavery - they are only half-right: the Civil War was about the South's frustration at not being electorally able to expand slavery beyond the South's borders.
Which underlines my original point: the colonists were denied their basic right to representation. The King of Great Britain held his throne pursuant to an act of Parliament - an act of Parliament that conditioned the King's jurisdiction upon his agreement to maintain representative government. The King violated his obligation to allow the colonists representative government and when the colonists formally sought redress from King and Parliament, both entities conspired against the colonists to deny them the basic rights that the whole post-1688 government of Great Britain was built upon.
The federal government jealously guarded all of the rights of Southerners and even extended to them special privileges other Americans did not have - the right to count non-citizens as citizens in their territories for electoral purposes, in order to give them almost 50% more Congressional representatives than they would have merited if they had been allotted on the basis of citizen population alone.
The colonists were insisting on their most basic rights.
The Confederates were upset that they were not given their own special privilege of vetoing any constitutionally-passed legislation they didn't like.
So in other words the Confederates felt that the government was no longer responsive to their needs as a people?