Behavioral euthanasia is a thing. If you think that she just got the dog, it was all fine and dandy, and then one day it killed a chicken, bit a dude but was otherwise a well behaved good dog, then you are naive. She most likely saw the writing on the wall earlier, worked with the dog (since it was meant to be a working, hunting dog), till the dog went too far and had to be put down. An article reduces all sort of things to a simple "politician bad", calling to emotion. The truth of the matter is she probably knows her shit more than any of us here, you don't get a working dog for the fun of it, as a pet, without knowing anything about them or how to train them. Some dogs can "come back" from aggression, some don't.

See Gold Shaw Farm on youtube, he has two working dogs. One, Toby, is very behaved, guarding the flock, not showing signs of aggression. The second dog he got later is Abby, which is an overexcited, dangerous to the animals dog. He trained both, in fact Abby came later, so he didn't make the mistakes he did with Toby. Yet Abby, after years of training, still shows aggression sometimes and needs to be reeled in. Abby has killed his chickens in the past. Luckily with her, she mostly targetted white chickens, not people or the entire flock, and she has a "paragon of virtue" in Toby, who also sometimes gets her to stop. Yet the owner spayed her, despite wanting to breed farm dogs, because he knew her behavior will probably end up in the puppies.

Now imagine what would happen, if Abby was so dangerous, she would bite people, kill chickens, ducks or geese. She would be out of there in a heartbeat. You simply can't have a working dog that does that. Same with the "failed drug sniffers" where dogs are too excited to work with humans correctly, or have other undesirable traits. They get adopted out of service at best, and if incredibly aggressive and dangerous to people, they get put down.