We on the "Yes on Prop 8" side are standing up for the rights of free speech and freedom of religion as guaranteed by the First Amendment.

You can still preach against homosexuality in the church or on the street. You can still ban gays from being married in your church if you so choose. In other words you still have free speech and religious rights.

The first amendment provides both freedom of religion and freedom from religion though. You don't have to have gay marriages in your church but niether can you use your beliefs to deny civil marriage.

Got it?