That's not necessarly true.  They love LIBERAL Christians.  But hate all the Christians that speak out against Homosexuality and Abortion, two subjects the city prides itself on (In the name of Liberty and Personal Freedom).  San Francisco has been gay since the 1940's, but didn't come out of the closet until the early 1970's when Mayor Masconi and Harvey Milk invited the LGBTQ all there.  San Francisco is the most ultra-liberal city in California, that is because of the largely LGBTQ population, abortion rights advocates and Hippies and Emos of all ages.  Christianity is fundamentally stands against the philosophies they hold dear, which are "Do what thou wilt, that is the whole of the law. Love is the law." and "Tune in, turn on and drop out" AND "Do your own thing, just as long as it doesn't hurt anyone else", Christians believe in following God's law and believe if you are "doing your own thing" you are actually following your own evil impulses.