It was flown by the morons who idolized the morons who wanted to keep slaves in the American south, and ended up getting their asses kicked. It's not even the real confederate flag, the second version of which looked more appropriately like the white flag of surrender (you can't make this shit up). It's the battle flag (ironic, because they absolutely sucked at battle) which was appropriated sometime after the war, as a means of intimidating freed blacks and other minorities. The design itself is fairly interesting (I thought so too when I was young), I can't deny that. But it also ironically takes cues off the British union jack, a country the US defeated to gain independence.
It speaks a lot about the herpy-derpy, inbred dumbassery that was the confederate south, and how they didn't have a single original idea...not even slavery. But some people will claim it as their heritage, because...well...they're not very smart.
en.wikipedia.org