Filing for an official civil marriage is basically announcing to the State that you are married. Talking Catholic doctrine here, the State has a right to know the marital status of each citizen. It's sinful to lie to the state about your marital status. Marriage touches on the basic unit of society, the family. It certainly extends into the jurisdiction of the State. There are some things that are none of the State's business, like schooling your children. But knowing your marital status is well within its bounds. In an ideal Catholic country, the State would be interested in giving certain tax breaks to married couples, as well as punishing any priest who attempts marriage. To tell knowingly false information to the State, which it has a right to know, is called fraud. Welfare deadbeats and other lowlifes commit welfare fraud every day. Criminals and scoundrels commit immigration fraud. Nice to see a Catholic bishop joining their ranks...