If you're offended or disgusted by the ISIS/ISIL flag, you should be equally offended by the Confederate flag.
Well, you have to remember the fact that more than a million Americans served in the Confederate army, out of which some 260,000 died. Tens of millions of people, in the Southern states such as Alabama, Louisiana and Mississippi can trace their ancestry back to these guys, who fought for the Confederate army. So it will not be right to demonize it.