“The officer, who was working off-duty security at the store”
If the officer was off-duty, then he’s not acting in an official capacity, and therefore should not be considered a “public servant” in this situation.
Davidson was in the wrong to assault him, but he should only face the charges he would be liable for if the security guard had been a “civilian”.
“Davidson was in the wrong to assault him...”
The story says the security guard assaulted Davidson, by grabbing him and shoving him through a door. Someone does that to me, I have a right to defend myself.
“If the officer was off-duty, then he’s not acting in an official capacity”
Not exactly corect. “Off duty” officers remains a police officer and retain all police powers anmd authorty.