The woman in your link was sex trafficked in Texas and California...where prostitution is illegal.
So where is an unbiased link to this statistic of yours?
Plus, saying legalization helps sex traffickers makes no sense.
Obviously if prostitution is illegal, it is FAR more difficult for a sex worker to run to the police...for fear of being charged. And the pimps can hold that over them as well.
If it's legal, all that goes away. They can call the police any time as they have done nothing wrong.
It's the same with drug use. Users do not dare ask for help to quit for fear of getting in trouble for using.
You make something illegal - all it does is force it underground and make it FAR more expensive and dangerous.