Other examples of...

Other examples of unification other than the Nassau Hall memorial include joint anniversary observances GAR and Confederate veterans continuing to this day at Gettysburg and other venues by reenactors from both sides. Even though our family has no personal history in the Civil War, it's been a topic of interest in our family including my Dad, me, and my reenactor son. Our family was at the 135th Gettysburg observance and we learned a lot about not only that battle but the war in general. He's an amateur Civil War history expert and we've toured several battlefields in detail especially 2 days at Gettysburg concluding with walking Pickett's Charge.
Yes the war was a tragedy, with several causes including economics, State's rights, and elimination of slavery. Do like we did, tour battlefields and get a sense of the heights and depths of that war. If you want to see monuments, check out Gettysburg where every Union regiment has some sort of monument (plus several on the confederate side). Check out the one day carnage at Antietam where the only monuments to the Generals on both sides are the six cannon barrels sunk halfway into the ground, muzzle down, where a general was killed. On our flight out to Baltimore for that four day weekend of touring, my seatmate asked what we were doing and when I told him, he asked why, probably thinking we were gun freaks, but I said it was more like trying to understand why men fight.
Yes, Jim Crow, States Rights, suppression of minorities, voting restrictions and other sins of the subsequent era are even worse than the war itself, but things are improving. We still have a long way to go, especially with the apologia and hardened attitudes of many. However, let's acknowledge that the generals and politicians were merely human, with positives and negatives. Absolutism is over simplification, easier than detailed study, but intellectually and morally dishonest.