Only on the "CBS This Morning" podcast, professor Ibram Kendi of American University tells co-host Tony Dokoupil that we're all trained to be racist and now we need to learn to be antiracist. In his new book, "How to be an Anti-Racist," Kendi traces the roots of racism and slavery back to Prince Henry of Portugal in the mid-1400s. He considers bigotry to be one of the three lethal weapons threatening human existence, along with nuclear war and climate change. Kendi also explains how racism harms almost everyone, no matter the color of their skin.