The rebel flag means different things to different people. I'm from Michigan and have no attachment to the flag, for the Dukes of Hazard for that matter. I, like many other people, see it as a symbol of oppression, as it was heavily used in the Jim Crow south as a symbol of white supremacy. Others see it as a symbol of pro slavery, some as a symbol of their southern heritage, where their family fought and died in what they viewed as northern aggression by a tyrannical centralized federal government. To some, it stands for sovereign states rights (I would disagree as you couldn't belong to the Confederacy unless slavery was legal in your state). tens of thousands of soldiers that never owned slaves gave their life under that flag standing up for their state.
I understand how the flag by itself can be offensive, especially if it were flown on a capitol building or other government or municipal buildings.
however
I am long past the point where we should deface a piece of history because someone is offended. The flag was JUST removed at Fort Sumter, where the first shots of the Civil War began. I don't like the move to erase history because history happens to be offensive.
Bubba owns the car, he can do with it what he wishes. But if he is afraid of offending someone, perhaps the better move would be to sell it to an enthusiast or a collector or something.