Racism Is So Confusing It Doesn't Even Make Sense To Itself

So yesterday I had the stressful time of unloading the last of the stuff from my childhood home. I took Tom Rowen with me to hold my hand. It wasn't too bad, actually, as the house looks so dang different now. The new owners (who haven't actually closed yet) have been redoing the floors and have a lot of furniture moved in (which irked my dad to no end).

I saw this bumper sticker on the back of a pickup truck.
And, apparently like the vast majority of the Internet, it confuses me to no end. I figured, it's racist. But I don't know why. And I'm in the North. Maybe they guy really hates the fact that so much cotton imported into the north was the result of the slave trade and if he'd only realized that he would have picked his own. Yeah, right.
I'm sure it doesn't mean what it says -- "If I had known the Civil War would have happened I would have picked my own cotton."
The Internet seems confused too. Scoot down this blog post. He has no idea either.
I expect it's something more like "If I'd know we'd have a black President(?)/unspecified problems which I arbitrarily blame on black people/something else I would have picked my own cotton."
I... I simply can't figure it out.
UPDATE: oh, apparently the original,from which this is minced, read (more clearly and racist): "if I'd known they were going to be this much of a problem, I'd of picked my own cotton."