"Prop 8 has only 1 purpose: to deny gay couples the protection of marriage."

I'm sure that a certain % of individuals who voted for it also supported the institution of civil unions - that would entitle gays to same rights as married couple. But these people care about the name/institution of 'marriage' maintaining its original (m+w) definition.

Therefore I personally would not rush to call support of prop 8 'anti-gay'.