The wife mentioned on camera that she was going to go get a gun. Under the circumstances that’s not a threat to be taken lightly. Before this all went down, the guy being interviewed was talking about being threatened and abused.
The reporter did the right thing by not fighting back. He had the presence of mind to know the camera was still running and that any amount of agression or hostility, verbal or otherwise, would have been spun into making it look like mutual combat rather than outright assault.
Because he held back the attorneys for the agent and his wife are now faced with a much more difficult defense. The prosecution can probably run down a number of people who have also been threatened.