Nice link about a person who thinks slavery was a choice (and leads a group with a whopping 40 members). Did you happen to read the very first sentence of the article?
"For many Americans, the Confederate battle flag is an unmistakable symbol of slavery and oppression." Sentence should have continued comma, no matter what the person flying says during the display.
OK, take at face value the Winthrop number, which is probably not warranted. So you proudly display a flag you KNOW is offensive to 77% of African-Americans in the South? Wouldn't that fact alone disqualify your claim of being one of the least racist posters? Seriously, rethink that self-image. And educate yourself on unconscious racism, the black/white baby study is way more instructive on the poll results than is any conclusion you might posit.
And lets talk about your days growing up in the South. What other conditions existed for the African-Americans that were near the flag? Could they walk the flag downtown to sit at a lunch counter and talk about pending legislation? Walk it down to register to vote? Fly it during a perfectly fair police investigation?
Your conclusion that "they" were proud in flying the flag then and are wrong to interpret it as offensive today is the height of narcissistic ignorance. No doubt you and your racist forbears saw that as approval of your racist society, but it was more likely along the lines of not looking you in the eye on the street (and no, that wasn't because they all were shy).
Can your conditioned to racism self even conceive of another reason they may have had to display the flag? Hint: self-preservation. Probably much lower chance of having their homes firebombed or getting lynched. You interpreted it as a proud display, they were just glad your KKK brethren looked elsewhere.