The idea for the ad came from FFRF co-president Annie Laurie Gaylor:
"You’re better than your church. So why? Why continue to attend Mass? Tithe? Why dutifully sacrifice to send your children to parochial schools so they can be brainwashed into the next generation of myrmidons (and, potentially, become the next Church victims)? For that matter, why have you put up with an institution that won’t put up with women priests, that excludes half of humanity?
No self-respecting feminist, civil libertarian or progressive should cling to the Catholic faith. As a Cafeteria Catholic, you chuck out the stale doctrine and moldy decrees of your religion, but keep patronizing the establishment that menaces public health by serving rotten offerings. Your continuing Catholic membership, as a “liberal,” casts a veneer of respectability upon an irrational sect determined to blow out the Enlightenment and threaten liberty for women worldwide. You are an enabler. And it’s got to stop."
Here's an excerpt from the ad and a link to the full ad:
"It's time to quit the Catholic Church"
"...It's your moment of truth. Will it be reproductive freedom, or back to the Dark Ages? Do you choose women and their rights, or Bishops and their wrongs? Whose side are you on? ...."