What gives the Catholic Church the authority to tell me, Congress and the rest of America that we all have to conform and accept their vision of "social justice" via legislative fiat?
You're willing to grant some people (members of the Catholic Church) their rights while denying others (those who oppose the forced implementation of "social justice") their rights.
What gives any human person the right to express his opinion?
That right is God given and Constitutionally protected.
So, you don't like the way somebody else is exercising his rights.
Tough.
That's your problem ... in this (still, more or less) free country, you'll just have to learn to live with people disagreeing with you.
That, or you can continue to look stupid.