Obama harvested votes from people convinced that his election would ease racial tensions.
Did his Facebook ads specifically take advantage of the fact that he was black? Did his ad campaign benefit from inflaming racial divisions?
To be fair, advertising from the trump campaign may not have played on racial tensions either. The thing people are upset about is the russian interference. The russians bought ads and made posts that clearly stoked tensions, and Facebook was negligent in preventing this.
That was not the claim. The claim was that he "harvested" racial tensions. And of course he did.