First, gold was not discovered in San Francisco, it was discovered in Coloma, which is about 140 miles north-east of San Francisco. Someone either didn't do his or her simple research or didn't care about the facts.
Next, I'm from the Bay Area, I lived in San Francisco for three years. I'm really sick of the San Francisco "gay jokes." They're just not funny. They never really were funny, and they're really not funny anymore. Most of the residents of SF are not gay. SF just happens to be a progressive city that accepts homosexuals as equals. This should be praised, not lampooned.