The general assembly by enacting this chapter intends to preempt any other regulation of the area covered by section 573.020, to promote statewide control of pornography, and to standardize laws that governmental subdivisions may adopt in other areas covered by this chapter. No governmental subdivision may enact or enforce a law that makes any conduct in the area covered by section 573.020 subject to a criminal or civil penalty of any kind. Cities and towns and counties of the first class may enact and enforce laws prohibiting and penalizing conduct subject to criminal or civil sanctions under other provisions of this chapter.