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.
If someone wants to question the jury’s reasoning, go for it; I can’t believe the video was the only evidence shown to the jury and they wouldn’t convict. I wonder what else they were shown that would even leave a conviction in doubt; I am quite sure our media won’t share it with us.