CCP Propagandist Claim US Made Some Americans Retarded

This is a video from CCP propaganda YouTube channel "WE ARE CHINA." The video's description "Without the consent of the Shoshone tribe of Native Americans, more than 900 nuclear tests were conducted in their territory by the American government. Over the past decades, Native Americans have always been unfairly treated, in a way that's beyond imagination. The American government must accept the responsibility for this. From Native American rights to the treatment of Black Americans, the #US is a pseudo defender of human rights that actually disregards human rights in practice."