Sean obviously does not do math. The odds of nobody in a few thousand black voters not making a mistake and voting for Romney are pretty small, but not zero. Philly has hundreds of all-black precincts all vying to be Romney-vote-free.
The rest of that article points out just how stupid it is for so-called conservatives to blame their loss on voter fraud. The obvious problem is increasing black stupidity. Blacks voted 10% for Reagan but only about 6% for Romney (or about 3% for black women).