The comment about letting it be up to the descendants of Confederate soldiers to determine what a flag means is ridiculous. The flag, like all flags, is a symbol. Symbols can both impart meaning to a cause, a country, a group of people (e.g., the American Eagle, as opposed to the American Turkey) but they will also gain meaning from what they represent. A good example is the swastika, which was a common decoration in many cultures up until its use by Nazi Germany. (Early printings of Rudyard Kipling books, that is, from the first part of the 20th century, often feature the swastika in the frontispiece since it was a very important Indian symbol.)

In this case, the Stars and Bars was flown by an army which defended (among other things) slavery. Its connotation is of oppression, and not by the North, but by white Southerners of black Southerners. When I see it flown, or on bumper stickers, I tend to treat it with contempt. Unfortunate, yes, but a flag which may have been fought for honorably and courageously is now typically used as a subtle indication of a desire for white supremacy.