Other mistake: In the battle for Fredricksburg you can see streaks in the sky from jets.
Other mistake: In the Battle of Bull Run, you can see that they use the same shot twice. It is a wide panoramic shot of the two armies. You see two explosions, one in the middle, and the second by the tree on the right.
Other mistake: In the scene where Gen. Jackson leaves the bedroom of his sleeping wife and child, you can see a modern light switch covered over by a piece of plastic and paint near the door frame.
Answer: Pride, honor, and respect were some of the characteristics of a Southerner's perspective during the Civil War, and did not change through the war. At this point of the war, however, the Confederates knew they were now on the defensive, no longer fighting for either slavery or states' rights, but the survival of their land, farms, and homes against foreign invaders (Union troops) who were using "scorched earth" tactics to break the South's will and ability to fight. That alone, kept them fighting even though victory was not going to happen for them.
What are scorched earth tactics?
Destruction of farms, crops, livestock. Also destroy every town that the Union troops arrive at.