A libertarian would further argue that (1) the availability of women who actually WANT to be in the trade would dry up a lot of the demand for those who don't, and (2) many prostitutes feel that they cannot go to the police if/when they are attacked; they have no defender except the pimp (who victimizes as much as defends).
Long time no see...how ya doin?
Market demands and yes, why seek help or treatment if it gets you busted?
"A libertarian would further argue that (1) the availability of women who actually WANT to be in the trade would dry up a lot of the demand for those who don't"
A libertarian would be wrong about that. The demand, as the article notes, is for attractive girls between 15 and 19, and those are precisely the women who generally do not want to be prostitutes.