Picking cotton is not a function that was wholly owned by blacks nor slaves.  

I myself grew up on a farm in Alabama, where my grandfather was a sharecropper (he never owned the land), and we were let out of school for 2 weeks in the fall to help pick that cotton.  And pick it, we did, and we also got paid by our grandfather, just like anyone else who helped him gather his crop, anywhere from 2.5 to 3.5 cents per pound.  In other words, an adult could pick cotton dragging a picksack and make 3 to 4 dollars at best per day.  Us kids made much less, but it was still helpful, because we were able to use the money to buy school supplies or shoes and clothing.

None of what Lou Dobbs said is relevant to your attempt to co-opt 'cotton pickin' as a rallying cry for your own brand of racism, and I absolutely resent it.