Here is part of Mississippi's Declaration of Secession: "Our position is thoroughly identified with the institution of slavery - the greatest material interest of the world. Its labor supplies the product, which constitutes by far the largest and most important portions of commerce of the earth. These products are peculiar to the climate verging on the tropical regions, and by an imperious law of nature, none but the…
However, I do take issue with narrow oversimplifications, and as such I would encourage you to do some research before making such blanket statements.
I have some people close to me who once wore t-shirts that had elements of the flag on them. If I were to ask them why they wore it, they would not answer or think anything along the lines of "overt racism." They're just people who have a bit of a redneck streak, are into country music, hunting, etc.
Symbols are what we make them to be. As someone in the design world I am very aware of this. Perhaps your experience is that everyone around you who sports the flag is an overt racist, but that hasn't been the experience for me. Do I still think it's misguided to use the flag? Personally, yes. But I think to paint the issue with such a broad brush doesn't do anyone any good.
Same thing about those "who think the Civil War was about anything other than slavery" - I think there's a solid case to be made for that among the "power brokers", but as is the case in history, things were much more nuanced, particularly for the rank and file. Search around a bit for why your average non-slave-owning Southerner signed up for the war, or even look at a guy like Robert E. Lee.
If you're interested in the nuances of the secession question, check out http://history.stackexchange.com/q/2056 - lots of good points on either end of the spectrum.
TL;DR: History is complex, be careful about blanket statements.