It really doesn’t matter what you think though.
That was the answer. She’s dead. It’s over.
And they are not going to be held criminally liable, because they are not criminally liable.
They were perfectly within their rights and the law, and so would have been anyone else she charged with a knife.
She was the danger here. Not the police.
You are correct, but I miss the days when cops were better, when they would assess the threat, in their own station, and resolve the issue without having to kill a little girl. Beanbag rounds, tasers, batons, rushing her with shields, locking her in a non-public area until she calmed down, etc etc etc. And yes, I've taken on a person with a knife before. I got a cut on my arm, but I disarmed them before they did any other damage. The cut healed. No scar.