Is The Law Against Bathhouses In San Francisco Legal?

in 1984 San Francisco forced all of its 14 gay bathhouses to close because it said they were the main cause of the AIDS epidemic at the time and the city still bans them, yet every other major city has gay bathhouses. New York closed theirs temporarily but reopened them, and there is even one in Berkley, right next to San Francisco. i don't see how San Francisco ever got away with this in the first place, it was the bathhouse customers' right to go in there and do what they wanted.