Why is san francisco always considered safe and snooty?

When SF is depicted in the media, or described by people it is always described as safe and snooty and such. I was wondering why this is? considering there are so many places in San Francisco that are very blue collar and people are not stuck up and there are actually city problems like crime. I meen There is the mission, Tenderloin, HP, Bayview, Visitasion Valley, Lakeview, Bernal Heights, Potraro Hill, Fillmore, Western Addition and other places all over the city that are not smug, snooty, and safe.