One would have to be stupid to think that blacks were fighting in order to preserve slavery. What's untaught in most history classes is that it is relatively recent that we Americans think of ourselves as citizens of United States. For most of our history, we thought of ourselves as citizens of Virginia, citizens of New York and citizens of whatever state in which we resided. Wesley says, "To the majority of the Negroes, as to all the South, the invading armies of the Union seemed to be ruthlessly attacking independent States, invading the beloved homeland and trampling upon all that these men held dear." Blacks have fought in all of our wars both before and after slavery, in hopes of better treatment afterwards.
Denying the role, and thereby cheapening the memory, of the Confederacy's slaves and freemen who fought in a failed war of independence is part of the agenda to cover up Abraham Lincoln's unconstitutional acts to prevent Southern secession. Did states have a right to secede? At the 1787 Constitutional Convention, James Madison rejected a proposal that would allow the federal government to suppress a seceding state. He said, "A Union of the States containing such an ingredient seemed to provide for its own destruction. The use of force against a State would look more like a declaration of war than an infliction of punishment and would probably be considered by the party attacked as a dissolution of all previous compacts by which it might be bound."