Linda Thomas-Greenfield, U.S. ambassador to the United Nations, told CBS’ “Face the Nation” in a segment that aired April 18 that the United States must not “whitewash” its history of slavery if it hopes to speak authoritatively on human rights, while responding to criticism for earlier saying that the “original sin of slavery” weaved “white supremacy” into America’s founding. “I was acknowledging what is a fact in the United States. Racism does exist in this country,” she said. “I think if we are going to be a voice around the globe for raising issues of human rights, we cannot whitewash our own issues in our own country,” she added. Thomas-Greenfield sparked controversy when she told Al Sharpton’s National Action Network conference last week that white supremacy was to blame for to the deaths of George Floyd and Breonna Taylor, and for continued discrimination against Muslims and Asian-Americans. “I have personally experienced one of America’s …