Scott Alexander has a great piece on tolerance and the red and blue tribes.
Among other things, it explains what Noah Smith meant when he said that "white" people move out into the country so they can be around only other "white" people. At the time, I had remarked that there were plenty of non-white people at my local redneck bar the very night that I read his post. But as Alexander points out, "white" is used as a code word by the blue tribe for members of the red tribe. So Smith was, in a sense, correct: The blacks and Hispanics who hang out at that bar drive pick up trucks, own guns, go hunting, and watch NASCAR races. This makes them members of the red tribe, and thus "white" in this classification scheme. And right as I was reading Alexander's piece, I was sitting in a Chinese restaurant with a black couple two tables away. The guy was chatting with the (white) people at the next table, and saying, pointing at the TV, "How great is this? Chinese food and NASCAR on the TV!" He was displaying his red tribe bona fides to fellow tribe members!
A very interesting point from Alexander's essay: far more white Democrats and Republicans reported that they would be upset by their child marrying someone of the other party than said they would by him or her marrying someone who was black.