The Confederate Battle flag[a] (really the navy flag, but who cares) is quite a controversial symbol in the US. Does it represent slavery, Jim Crow laws, oppression and general nastiness, or is it a symbol of people fighting for their rights to run their society the way the want? (The best explanation I've heard is that "the south fought for their freedom to deny other people's freedom".)
Here in Vienna the confederate battle flag symbolizes smoking pot and Che Guevara, at least according to the Rebel Shop[b]. No word yet on what the Sons of Confederate Veterans[c] think of that particular use.
Note: The "13 FTW 69" on the Rebel Shop logo is from the label of "Wanted" beer. No idea what it means. The civil war raged from 1861 to 1865, so 1869 is right out. Anything rebellious happening 1969 was probably steamrolled into a footnote of history by the Apollo landings[d] that year. (Apollo 13 was in 1970, so that one can't be it.)