Why Protest Gay Marriage in San Francisco?

Don Surber asks a good question:

Should not the opponents of Proposition 8 go to the places that supported defining marriage as between one man and one woman?

I must be missing something. San Francisco overwhelmingly supports homosexuals. Its mayor defied the law and recognized gay marriages.

So why did gay marriage proponents protest in San Francisco? They blocked traffic. Police arrested 175 protesters.

Given that white males dominated the protests and black and Latino voters voted about 70%-30% to ban gay marriages, it might be that the protesters feared going into those neighborhoods.

I asked similar questions when the activists were marching outside Mormon temples in November while taking great care to stay out of South Central where the voters overwhelmingly approved Prop 8.