This is not an extra rule that would contradict with God's laws; instead, it promotes and defends them.
11. Thou shalt displayeth the Ten Commandments in all public places.
Like it or not, there is no Separation of Church and State. It says nowhere in the Constitution of such a policy. However, people have the right to not be oppressed by a particular religion, but they still can't have that religion taken away from people.