Just because a dog is "trained" to fight doesn't mean that it can't be rehabbed and placed in a good home. Look at Michael Vick's dogs that have good normal lives now, some in multi-dog households. Look at how many puppy mill rescues grow into people-loving individuals. Many dogs can be rehabilitated and retrainted. However, it DOES take a lot of patience and resources that are not always available obviously.
But someone mentioned that the dogs are 'used to eating human flesh' (I didn't read the article yet, I'm just thinking in terms of what's been said here), I can understand why culling the population would be necessary. Its one thing to manage a dog-aggressive dog, human aggression, especially unprovoked, is a different matter. When its either your children's survival or that of a feral dog, the children win in terms of priorities. And yes humane would be ideal but Americans neuter livestock without anaesthesia apparently, and I'm not sure which weighs in as worse on the ethics scale. If you don't have the money then you don't have the money.