I think even the cop knows he did something wrong, the question was whether or not it rose to the level of a manslaughter conviction. From the perspective of a firearms instructor, it looked like he reverted to training — his actions were much too fast to include any sort of rational contemplation. In the eyes of a jury, this may have been enough to inject a reasonable doubt.
That all being said, if people want this to get better, we need to address the training and use-of-force guidelines for this police department (and likely others), so that the instantaneous response to this kind of situation does not immediately escalate to lethal force. The cop could have created more distance, moved to cover behind his patrol car and given orders over the loudspeaker, and ended the stop safely for everyone — but not if that wasn’t how he was trained.
To be clear, anyone trying to cast this as a black/white problem is simply going to make the problem worse — this is a police training and use-of-force guidelines problem, and we can pursue that without demonizing cops.