A San Francisco city official who organized a walking tour meant to showcase the “squalor” of downtown is resigning, Mayor London Breed’s office confirmed to SFGATE. Earlier this month, a posting appeared on Eventbrite that promoted a “Downtown Doom Loop Walking Tour,” angering local residents and raising questions about the event’s seriousness and the identity of its anonymous organizer, who described themself as a city commissioner. The tour was scheduled for Saturday but was canceled by the organizer Friday, which prompted some Eventbrite ticket holders to seek a refund. Alex Ludlum, who served as the vice chair on the city’s...