It's a symbol of racism and of treason, regardless of how you slice it. There are those who grew up around it who don't look at it as a reminder of either because of its prevalence in Southern culture (i.e. the General Lee of Dukes of Hazzard fame), but in the end, it is a banner representative of the treachery of the Confederacy and has been used as a symbol of terror against people of color in the South. So even if there are those who see it merely as a symbol of "Southern pride", it's still a toxic symbol that has no place in today's society. There is much to be proud of in the South, but the Confederacy and the sordid after-effects of Jim Crow and the Lost Cause ain't it.
stephen pretty much nailed it but of course America being a paragon of freedom and free speech can't remove the flag (ie the way Germany has every piece of Nazi material). That is going to be a source of far more ugliness unfortunately