Give Jackson a Darwin Award.
The only thing the story was missing was a crying grandmother saying "He was turning his life around".
I hear the Elvis song "In the Ghetto" playing in my head when I read this.
What was he supposed to do???
He complied with their request.
If he'd refused to pull his hand out, they might very well have released the dog on him, too, and said that he had refused their request. If he'd let go of the gun and it had fallen to the ground, what if it had gone off (or even if it hadn't, he'd have been endangering others).
Note that the chief didn't say that the victim pointed the gun at anyone until the dog was released and he defended himself.