Answer:
African Americans knew that if the Confederacy came victorious, they would be returned to slavery even if they had already gained their freedom thanks to the Emancipation Proclamation. In other words, their liberty was at stake.
It is important to clarify however, that over half of African American deaths during the Civil War were due to disease, and not battle wounds. This is because most African American soldiers were not sent to battle, but were put in guard duty, or tasked with building forts, and in crowded conditions, which helped spread diseases more quickly.
