I’m sure shooting a fleeing and unarmed suspect can be justified (if the shooter was the Unabomber, for example - a clear threat to others’ safety if loose/free). I don’t know the rationale for the North Charleston cop’s shooting of the unarmed man (I saw the footage), but I don’t second-guess juries. IIRC, they didn’t acquit the cop; they just wouldn’t convict him (hung jury or mistrial) - and I’m sure the jury had more information than our “free press” ever shared with us.
The LA cops were actually acquitted by a jury, who saw the whole tape of the incident (in which Rodney King initially attacked them); our ghetto denizens rioted because our “free press” showed us only the second half of that video.
We second-guess juries all the time. We've all seen the video. And I for the life of me do not see how that shooting was justified in any shape or form.
As for why the cop shot, the most likely answer is that he was one of the small minority of police officers who should not have been police officers to begin with. Who panicked and used deadly force when none was justified. The overwhelming majority of police officers do their very difficult job quietly and competently. It is the small minority of officers, like this one in Minneapolis or ones in Georgia and Oklahoma and Nevada and Ohio and South Carolina and far too many other places, who panic and overreact, and people die as a result. I think that this officer should pay a penalty for shooting Ms. Diamond. I thought the cop who shot people in a lot of other situations should pay a penalty for their overreaction, too. But all too often they do not, and I will not be at all surprised if that is the case here as well.