...And Their Flags
One person's "disgusting piece of trash" is another person's honored symbol of brave ancestors who endured unimaginable suffering to defend their land and people.
The north/union had no moral authority to invade the South, lay the place waste and keep the region in economic peonage for about five generations thereafter.
Yes, northern states abolished slavery within their borders, so northerners didn't have slaves living in their back yards anymore, but that gave them no moral authority -- they were still armpit deep in slavery. Northern textile interests got rich processing Southern, slave-grown cotton in their mills. New England maritime interests got rich shipping Southern, slave-grown cotton to Europe. Northern banks got rich financing the purchase of plantations and slaves, and northern insurance companies got rich insuring slaves. If the north had really wanted to end slavery, all they had to do was quit buying the cotton. But they didn't, and that is why they did not have the moral authority to send a brutal army south to kill Southerners. They profited from slavery as surely as any plantation owner, but without the expense.
The states of the "first wave" of secession seceded in part (primarily) to protect slavery (although other reasons are also listed in the secession declarations). The states of the upper South seceded later, after Lincoln ordered them to provide militia to invade the seceded states. So some of the states seceded partially because of slavery; but all of the Southern states fought to protect their homes, families and communities from a brutal army of invasion. (And, no, secession was not treason. http://youtu.be/7qfX0uXDktY)
The lack of moral authority continued after the war. Thanks to poverty created by northern economic oppression (policies of private industry but allowed by the feds), pellagra and hookworm sickened and killed Southerners, black and white, by the thousands well into the 20th century.
After the war, carpetbagger legislatures drove some Southern states so deeply in debt, the taxpayers of those states didn't get them paid off until the mid-20th century. (A lot of the money was spent on the carpetbaggers' personal enrichment.) There was little money for infrastructure, education, etc., for literally generations, because of carpetbagger debt and continuing economic oppression. (Google "Discriminatory Freight Rates" by Carole E. Scott and see one method by which it was done, which did not end until 1952. Read "Born Fighting" by Senator James Webb to see the effects.)
Because of things like this, the South is ridiculed as backward and uneducated. That's like beating up a woman and then ridiculing her because she bleeds.
It was a war to free slaves? No. Emphatically, no.
Yes, the flag has been misused by some groups, but so has the US. flag. And if the Confederate flag "flew over" slavery, the U.S. flag "flew over" the the country's warring against American Indians, stealing their land, decimating whole tribes and herding them into reservations in conditions worse than plantation slavery. It was official US government policy to allow killing off the buffalo to starve the Plains Indians to extinction -- so settlers could have their lands.
It's delusional to imagine the USA was morally superior to the Confederacy when you look at the whole of each, and not wear blinders that allow you to focus solely on slavery (which the north was implicit in, but which is blocked out by the blinders). And that is why so many Southerners honor the Confederate battle flag -- to acknowledge and honor the memory of Southern men who defended their homes, families and against the a brutal military invasion.