More likely that the forces driving the legislation (which are very anti-sex, period), and the Congress critters willing to jump on board (who know their base),

More likely that the forces driving the legislation (which are very anti-sex, period), and the Congress critters willing to jump on board (who know their base), don't know and/or don't care about whether the boon it provides to law enforcement outweighs its visibility re: trafficking. A lot of morals based legislation is driven by worldview, not by data.