Laws prohibiting sex work are based on a moral code that doesn't fully consider the implications. If we are going to reform non-violent crimes like drug use and selling that are founded on societal beliefs, we also need to consider other non-violent crimes, regardless of stigma and moral objections.
Look -- we get that you're under time pressure and for last minute news overviews, it's easier to just cut and paste from press releases. But if repeated research and in-depth features indicate that the press release is not a complete or accurate description of what happened, this becomes dishonest reporting.
You don't have to approve of the buying and selling of sex to see the wisdom in Amnesty's proposal. I'm certain that humanists, along with everyone else who considers themselves a civilized human being, would join unanimously to oppose human trafficking. However, the conflation of these evils with consensual commercial sex is wrong.