A street in St. Francis Wood in San Francisco, Calif. A San Mateo County official compared pro-housing activists to Nazis in an explosive tweet Sunday, the latest salvo in a battle over whether to build denser housing in the wealthy San Francisco neighborhood. MICHAEL MACOR/The Chronicle (2004) The president of the San Mateo County Harbor District compared pro-housing activists to Nazis in an explosive tweet Sunday, the latest salvo in a battle over whether to build denser housing in a wealthy San Francisco enclave. “Class war news of the day: Today some Nazis, I mean YIMBYs, are casing St. Francis...