That's pretty much the case with just about every "sex trafficking" bust, isn't it? Lots of talk about rescuing children and what not, but in the end women, who are supposedly being helped, are hauled off to the slammer, customers, too, and not a single trafficking victim is found. But that doesn't make for good headlines, so the latter part is rarely reported.
Backpage got caught in a perfect combination of "baptists and bootleggers" where, except for people who actually do try to help trafficking victims, exploited kids, etc., who all found BP quite useful and cooperative, everybody, left and right, wanted to shut it down for purely ideological reasons. In the end, nobody came out ahead.