It appears the vandals are upset about the Catholic church's support of Proposition 8, which made same-sex marriage illegal in California.
But, the Most Holy Redeemer Catholic Church on Diamond Street is gay-friendly. Many parishioners voted against Prop 8 and they are upset their church was targeted.
"We're very disturbed by the hierarchy's support of the Yes on Eight Campaign. We've been in conversation with the bishop, which is the way I think we need to handle it. I think Catholic teaching shows us we're all a community and we all need to talk to one another about it even if we have disagreements," said Rob Hopckey.
San Francisco Police are investigating the vandalism.