Isn't slavery tyranny?
Regardless the bad history many bluebellies were taught, the war was not fought, by the Confederate fighters, to keep slavery. Slavery was instituted by the Brits and wealthy land barrons, many from the north, not by the poor guys that were fighting and dying for Southern Freedom. Unlike the Union, the Confederate soldiers were volunteers. The Union started the war to force the South to pay higher oppressive taxes than King George had imposed on the Colonies.