I mean, it’s not all about white racists, or else Obama would have lost.
It’s worth reading the article. First of all racism was the main reason, but not the only reason. The data bears this out. And secondly, neither John McCain nor Mitt Romney were making explicit appeals to racists. To white supremacists, there really isn’t any difference between a black president and a white president who doesn’t think he’s inherently better than black people. So racists decided Romney/Obama on non-racial terms (economics), or sat it out.