First of all, it isn't fair to blame this guy, and his T-shirt, on Mitt Romney's campaign. Tomorrow, someone is probably going to wear something equally offensive to an Obama campaign event, so, you know, both sides do it. Someone with some common sense should have thrown him out of the event, and they should have made certain that there were seven or eight cameras present when they did it. That would have been a positive story for the Romney campaign (albeit, one that would have infuriated their base, but still).
Second, the freak-out over this T-shirt should be placed firmly in the category of "business as usual." There are a good number of people in this country who, thanks to things like the Tea Party and their enablers in the Republican Party, just hate the person in the White House. They hate who he is and they hate what he stands for. It is a searing hatred that ignores the facts, ignores common sense, and burns with the intensity of a thousand suns. They just hate him. They're not afraid to be seen in public expressing that hate.
Third, I say let this guy have the American he thinks he wants. He wants an America where everything is okay because there's a white person in the White House. If that's what he thinks America really is, let him cling to his fantasy and let him imagine that this isn't a richly diverse country where people can still overcome tremendous obstacles and become President. Let him pound sand in the face of change.
Because, let's face it. The guy in this shirt has a lot more in common with where Barack Obama came from than where Mitt Romney came from. The greatness of America is evident in the fact that someone with Obama's name, identity, class status, and background can become President of the United States. Mitt Romney's dad ran an American car company, was governor of Michigan, and ran for President. Now he's running on that leg up in the world. I'm guessing that the guy in this T-shirt didn't have a father who had a long and storied career in business and politics and made a lot of money that he could then use to give his children a running head start in America. I'm guessing that his background is a bit more modest, just not that of a person who is half-black.
Even if Obama wasn't black, they'd still hate him because he's a Democrat. But let's not kid ourselves--they just hate him. And that's why so many people are standing next to this guy. So, yeah. It is about him. He wore the thing. But the people standing next to him ain't exactly up on what it is that makes America great, either. They are complicit in the act of denying what makes America a place too good for them to appreciate.