Some people seem to think that nations have no business in promoting morality in general or sexual morality in particular. There's not always a cogent reason for this objection, but often the presupposition behind the objection is that there is supposed to be separation of church and state, and that this separation should entail the state being concerned with "secular" things and the church being concerned with "religious" things. Morality is then identified as a "religious" thing, and so the objection concludes that the state has no business addressing issues of morality.
The Bible provides a counter-point. While there is separation of church and state in the Bible's example of the monarchy of Israel (the king was not the high priest, and the high priest was not the king), there is also significant areas of overlapping concern. The king (not the high priest) was supposed to enforce a lot of laws that clearly were designed to regulate morality, while the high priest was supposed to provide for sacrifices for sins.
Some have imagined that the example of Israel is not set forward to be an example for the nations. On one level, that's true. There are certain aspects of Israel's system that have passed out of existence. The old administration of the worship of God has passed away, particularly in view of the coming of the last and greatest priest, Jesus.
Nevertheless, church and state remain. Thus, the question remains - whether the state, as such, should be concerned about righteousness.
The Bible has the answer:
Righteousness exalteth a nation: but sin is a reproach to any people.
My point is not to emphasize the word "any," which is added by the translators, but rather to emphasize that this is presented as a gnomic truth (the point the translators conveyed with "any"). Sin and righteousness are something that leads God to treat nations as nations in a particular way. Thus, nations as nations have an interest in promoting righteousness and suppressing sin.