It's plausibly deniable that you're contributing tithes specifically to take rights away from gays. It's hard to deny that if you're contributing to Prop 8.
I would make the argument that contributing the Catholic church is far worse for homosexuals, children, women, and the planet than Prop 8 ever could be. But then again, that's why I don't go around making check lists of appropriate contributions for everyone in my company around me...
