Actually, if you read books in the world, and hear all dialogues, it makes not just perfect sense, but pretty much explains and adds to Anna's tragedy.
1. In one of the books we learn who this spirit really is, and her relationship with the Ladies.
2. Children always lived in the swamps because it was how the villagers paid for their protection. Villagers sent the children, the Ladies eat them, and all was well. Anna got posted here as was her payment for their "help" with her unborn baby.
3. Anna pretty much committed a cardinal sin by making a selfish and hateful deal with the Ladies - she asked them to kill her unborn baby, probably having no idea that their powers come from dead children. The villagers know the price and never run to the Ladies with their little crap, you know, only when they require a real protection, and their lives are in danger. The Ladies made Anna to pay in a very karmic way - made her to guard their future meals, now in full understanding of what is going on, and what she has done. That's why she started to loose her mind.
4. It was glaringly obvious that releasing the Spirit would attract an immediate attention of the Ladies, and it was exactly what the Spirit expected. It is similar to committing a crime in order to drive all city police to one place, and not to interfere with another crime. Without the Ladies watching, Anna let the children escape. When she does this, the Ladies curse her for it. If she does not have a chance - the children are taken to be eaten, and Anna looses her mind completely.
In my opinion, these two interconnected plot-lines - Family Matter and Ladies of the Wood - are a masterpiece of story-telling in games, and nothing from TW3 comes even close to them.