President Joe Biden on Monday denounced racism at the South Carolina Black church where a hate-filled gunman killed nine parishioners in an effort to underline his support for racial justice as he starts his reelection campaign. The president’s emotional return to the scene of one of the nation’s worst racist attacks is aimed at reminding Americans of the danger posed by white nationalists and right-wing Republicans like former President Donald Trump. “The truth is under assault in America and as a consequence so is our democracy,” Biden told an enthusiastic crowd at Mother Emanuel AME Church …