Ta-Nehisi Coates notes the white privilege issue behind Tagg Romney's anger at Obama. This reminds me so very much of the 2008 election when whites usually saw McCain's anger as a good thing. It revealed his passion and his dedication. But when people used the words "anger" and "Obama" in any context, with either of them, it was a negative. Most of my white friends didn't even acknowledge this, because I really don't think they could see it.
The same thing applied to Sarah Palin and her knocked up daughter. Put that in the Obama family, and add the "local thug father" to the picture, and the right wing would have exploded with righteous anger. This, they would have said, revealed a lack of morality in the Obamas. But with Sarah, it was just fine. And in fact, was a good thing.
Now, the spoiled rich white kid of a spoiled and racist liar Mitt Romney can get away with threatening to punch Obama in the face, because, as Coates says it, "Yes because a good whippin' would teach that Obama boy to mind his place."
I don't know that Tagg Romney is a racist. I suspect he isn't any more than the rest of us. But that is the point of white privilege. It doesn't even dawn on him, or any one around him how that would not work the other way around.