Well, it seems a bit steep for a guy with an SLR taking a couple shots, but it doesn't seem to be a ranger misinterpreting things in an over-broad way. It actually does look like policy.
http://sfrecpark.org/PermitsAndReservations-FilmVideoPhotoProduction.aspx
"Commercial film, production is defined as any activity that results in a film, video or photograph being sold, or any activity involving filming or photography for which crew and/or talent is paid. This includes "non-profit" productions. This also includes wedding pictures if the photographer is paid. It does not include photography or video for personal use, however tripods even for personal use are restricted in certain areas."
I'd say find another suitable alternate location to offer clients. Let your clients choose, knowing that in order to shoot at that location you need a $231 permit, and that you'll pass that cost to them directly (ie: no profit will be made on the permit). If their hearts are set on that location, $230 won't stop them. If it was just a nice idea, but your other location is just as good, hey, you saved them money.