Three remarkable San Francisco nonprofit hospitals — Kaiser San Francisco, St. Mary's Medical Center and California Pacific Medical Center — are the latest targets of a recycled political attack by the Greenlining Institute; an attack that's not only wrongheaded, it's been discussed, discredited and rejected by the Legislature for two years running. The truth is, these hospitals make meaningful contributions that improve community health and provide care for the underserved and uninsured. Greenlining's goal, in league with their political ally, the California Nurses Association, is to question if these hospitals deserve their tax-exempt status in exchange for the community benefits that they provide.