Living in the South, I see confederate flags quite often. When I do, I give them the middle-finger salute. The confederacy is a thing of the past. Now, all 50 states are part of the UNITED States. Slavery is a thing of the past, and we don't need to be flying confederate flags to remind us of that horrible practice.
I like to ask them if they support the 2nd Amendment. Of course "hell, yeah!" is usually the answer ... and then I remind them that the CSA didn't. So, it's either the confederate flag, or the US flag ... but not both.