Sure it was. Just read some of the quotes of the Southern leaders at the time of secession.
...Lincoln ignored the four slave states in the Union and said he wanted blacks expelled from the US altogether...
Lincoln didn't ignore the 4 slave states that did not join the Southern rebellion, he could not Constitutionally do anything about them until he gained passage of the 13th Amendment and sent it to the states for ratification. As for your claim about wanting all blacks expelled from the U.S. altogether, that is a flat out lie.
Sherman is infamous for it and more than a few northern generals graduated from his example to wipe out the Indians.
And when did that happen?
This war, like most wars, was about money and resources.
Oh yes, state's rights too - basically money and resources.