A protestor recorded threatening to harm a San Francisco GOP chairman in a viral video has been identified as a local hip-hop DJ and public school social worker. Stefan Goldstone, who performs as “DJ Sake-1,” accosted John Dennis, 56, last Saturday at the Civic Center in downtown San Francisco during a cleanup event organized by Trump-supporting activist, Scott Pressler. Mr. Dennis is running as the Republican candidate against Speaker of the House Nancy Pelosi. In a clip posted on Mr. Dennis’ Twitter account, he speaks to the agitated man who confronts him. “Why are you so angry? I don’t understand....