Opening fire on the wrong people, especially those who were doing nothing wrong or threatening in any way to the officers, is not a “mistake.”
You are welcome to be at the receiving end of such a “mistake” and see if you are still sympathetic.
The incident I referred to involved the wrong make and color of truck, and the two women inside looked nothing like the suspect they sought. The police tried to kill them anyway.
But, the police said it was a mistake. Can you prove otherwise?