Is it legal to park at the median divider on Sundays in San Francisco?

I did this last night, in a huge line of other cars do so, and I got a 63.00 ticket. I assumed that “church parking” was legal, at least in the mission because everyone always does it. I have looked for an actual rule but can find nothing. Does anyone know the actual rule or amendment to the rule? Or is this just illegal but people do it anyway.