So.
Walmart, E-Bay and NASCAR are all government entities?
How do you like them apples?
No they are private entities doing what they are doing through their own corporate decision to pander to the crowd, and not due to any government pressure to remove the flag. They are free to not sell Confederate memorabilia just as companies like Dixie Outfitters are free to continue to sell it. We, as consumers, are free to withhold our spending at those companies because of their stance.
How do you like them apples?
Not much. I'd boycott them in retaliation myself except that I already don't shop at Walmart, don't use Ebay, and have never watched NASCAR so it'd be a pretty hollow protest if I did.