The rapper Eminem struck out at President Trump in a video that played at the BET Hip Hop Awards on Tuesday, accusing the president of racism, hypocrisy, disrespect of military veterans and more in almost five minutes of furious freestyle rap. He also excoriated Mr. Trump for his responses to the recent violence in Charlottesville, Va., the devastation in Puerto Rico from Hurricane Maria and the mass shooting in Las Vegas. The video, titled “The Storm,” was filmed in Detroit as part of the BET Hip Hop Awards’ traditional cyphers, in which rappers typically aim to deliver showy verses in...