I do see what this film is aiming for; a very cynical depiction of how society grinds down those at the bottom, then tut-tuts in horror when they do whatever is necessary to survive. This film is inspired by a true case which came to light in 1964; over the previous decade, young girls had been forced to work as prostitutes by two sisters (Doria and Llausás), in horrendous conditions, and beaten or killed if they tried to escape or were of no further use [Reports say they killed at least eighty women and ten men, making them the most prolific serial killers I'd never heard of, though the body-count here is much lower] When arrested, the madams who ran the brothel are remarkably unrepentant, saying that everyone knew what they were doing, and far worse people are allowed to walk the streets. Certainly, the argument that "society's to blame" is given some credence here; their client list, as they move from city to city, includes high-ranking officials and the military.
There are a number of chilling moments, most notably seeing how the humanity is relentlessly drained from one of their victims, Adelina (Bracho), during the conversion to her new life. She was (unwittingly?) sold to the madams by her father (Hoyas), and the other half of the film concerns his struggles to retain his land. This aspect, apparently some kind of socialist political commentary, is stunningly pointless and fails miserably, unless Cazals' aim was to suck all the life out of his film. It's a shame, since the rest is effective and surprisingly even-handed: the madams are as much abused as abusers, the authorities are as intent on sweeping everything under the carpet as investigating, the press just want the lurid details to sell papers and the victims are only of interest, in so far as they can serve these ends. If Cazals had stuck with this as his central concept, the results would have been a much more effective and disturbing portrayal of how society can go really bad. A final note: the killers got 40 years, so if they are still alive must be out of jail...