The Confederate flag that is commonly flown was not the flag of the Confederacy, if anyone looked at history they should know that. It's surprising that they regard the Confederate flag as offensive and not the American flag.
The flag often referred to was nothing more than a war flag so armies could tell one another apart. It was never used in the "south" prior to that.
Yes, it represents a part of American history, no different than the colony flag or any other historic flag. You can't forget that slavery in America started in the Northern Colonies. Or that Union states were allowed to have slaves. As a matter of fact, those Union states kept slaves until 1865, after the Civil War had ended. So, they freed slaves only to segregate them around a decade later. So, in truth, the American flag would be a symbol of oppression, not just a regional flag.
But, there's so much propaganda and so few who see with logic and not raging emotion, it's a losing battle.
Edit: @ The Intellectual- There has been no genocide in America and to compare the two says much about your lack of awareness. They weren't exterminated. Slavery was an oppressive institution, and no where did I say it wasn't, and one practiced not only by America, but also by Europe. It was initiated by the Spanish. If you actually think a regional flag symbolizes a practice maintained by an entire nation (and much of the civilized world), think again. If you don't like the flag, don't fly it. But, put the blame where it lies. The American flag would be the oppressive symbol.
Equating it to an Al-Queda flag is equally laughable. Do you have any idea why the states left the union? Here's a hint, it's called "taxation." Those issues started in the 1820s. Why on earth would one country attack another over a practice that was allowed? As I said, Union states had slaves until after the Civil War ended. States' rights was the reason for the conflict.
Yes, the flag does represent a war during America's history. A war that claimed the lives of millions of Americans.