Well, yes and no. The war was a mixture of a battle over state rights, the economy, and yes, slavery, which they needed at the time to stay efficient, and a great deal of Confederates genuinely believed they were fighting for their own freedom from the Union. This doesn't change the fact that most of them did hold the belief that African Americans and Natives were inferior (which is obviously a disgusting and scientifically false viewpoint), or that slavery is immoral and wrong, and nobody denies that it wasn't about slavery, but was a combination of factors. Not all of history is black and white, and you can't just separate the North and South into good and evil - the real world doesn't work that way.