Nope. Slaves stayed slaves in the Union slave states. The war wasn't about freeing slaves, it was about enslaving the people who defied DC and it's control of the money.
The other 200,000 died to keep the slaves.
Died because people invaded them and killed them.
The North did not have good motives. They were the aggressors and their reasons for invading were not benign. The people who died defending their homeland had good motives.