Being black was a net negative for a presidential candidate. There's a reason why it took decades before a black person could finally become the nominee of either Party.
The 21st century is not decades ago. No, being Black is not a net negative at all for a candidate. Take a look at the 2014 Oklahoma Senate races if you don't believe me.
Okay I realize you are most likely smeone's sock, but Inhofe was a deeply entrenched Senator while the special election was an open seat. In spite of that, the black Democrat only got 3k more votes than the white Democrat.