Yes, the options are very little and so someone is willing to pay them, not out of the goodness of their heart obviously, and now they can go home and their families can eat a little bit better and live a bit better than they could have before. I'm not saying this is some ideal fantasy land for them but at the same time, westerners have a habit of imposing their own way of life on others without any thoughts to the why the situation is like that in the first place and what the alternative may be.
Like I stated, in India, there were negative consequences that were much worse than working in a factory at a young age because of westerners butting in and basically taking away one of the minimal employment opportunities those girls had. I'm sure you would agree being a prostitute where you exposed to disease and possibility of being imprisoned and even killed by johns is a little bit worse than working in a factory right?
Also the article mentions "They make as little as two dollars a day" which in the US is obviously dirt but in the Congo I imagine it might be a bit more money. What is the cost of bread in the congo for example?