I don't think there necessarily needs to be a statute against swearing in and of itself. Disorderly conduct laws should suffice to encompass situations that merit swearing that may have a detrimental impact on what is expected of people in public venues. Are you going to arrest everyone in the crowd at a Slayer concert at the local ampitheater? No, because its not distracting and is expected. Someone cussing loudly in a library? Yeah, they need to be disciplined.