Private Thoughts vs. Public Actions

While the state lacks the jurisdiction and the means to judge the interior movements of the heart, this is a limitation of human authority, not a moral validation of sinful thought. The state remains restricted to the external forum, regulating words and actions in order to preserve the common good. However, when a sinful imagination is deliberately consented to by the will and is then externalized through speech or other expression, it ceases to belong purely to the private interior forum. It becomes an external act that manifests the disposition of the will. When such expression is made public, it can constitute scandal, the encouragement of wrongdoing, or even a declaration of intent, and therefore may fall within the legitimate concern of civil authority in its duty to safeguard the common good.

Therefore, when you have lustful thoughts and internally consent to them, it is a sin, yet you remain beyond the reach of the state. You are answerable to God, however, and are morally obliged to confess this in the Sacrament of Penance. But when you begin to speak of these thoughts in an unnecessarily explicit manner — and instead of condemning them, you trivialize, justify, or even celebrate them — you commit an entirely new sin. At this point, because your interior struggle has been manifested through word or deed, you are no longer untouchable by human authority. To argue that, "Oh, but that's just my imagination," is nonsensical. As far as the state is concerned, it is the manifestation of your evil thoughts that makes you liable, not the fact that you have a dirty mind. You could have just shut up and gotten away with it clean (not from God, though), but because you abused your verbal faculties and decided to give a platform for your filthy heart, it is right and just for you to be publicly disgraced. You brought that upon yourself.