The idea of a flag representing racism is absurd, just about every nation on Earth has had some kind of institutionalized racism in a national history. The real issue is as you pointed out, our nation being divided and engaged in a conflict of American killing American. The highest American body count of any War that America was engaged in. Historical buildings should have what was there at the time. If someone wants whatever flag on his grave, then fine, do it. Official government buildings in use by state government should not.