It was a strange moment of triumph against racism: The gun-slinging white supremacist Craig Cobb, dressed up for daytime TV in a dark suit and red tie, hearing that his DNA testing revealed his ancestry to be only “86 percent European, and … 14 percent Sub-Saharan African.” The studio audience whooped and laughed and cheered. And Cobb — who was, in 2013, charged with terrorizing people while trying to create an all-white enclave in North Dakota — reacted like a sore loser in the schoolyard. “Wait a minute, wait a minute, hold on, just wait a minute,” he said, trying to put on an all-knowing smile. “This is called statistical noise.”