You see two cops in a pinch defending themselves. I see them executing a citizen without making even the slightest attempt to resolve the situation peacefully.
I think the police have a moral responsibility to always try to resolve the situation peacefully first, no matter how dire the circumstances. And if that fails, they have a responsibility to resolve the situation without death, theirs or anyone else's. My problem with these guys is not that they didn't stand there and let a dude stab them, that's a massive misrepresentation of my argument. My problem is that they went straight to the gun - instead of 'let's get everybody, including us, out of this safely' it was 'obey or die,' and that is too far of a leap, and a failure to perform the basic duties of the job. Protect and serve, not comply or die.
I don't intend to seem callous - if that guy had injured or killed either of those cops, it would be a tragedy, hell would rightfully rain down on him, and if he survived the encounter he would never get out of prison.
But being cops means never shooting first, because good guys don't shoot first, no exceptions. It means assuming the risk that goes with never shooting first. Cops are supposed to be the best of us, and that's why, and I don't think it's unreasonable to expect them to act as the best of us. I don't think it's unreasonable to have very high expectations for the on-the-job behavior of people who have the authority to arrest and kill. I wish they were paid better and trained better, too.
I think that would really go a long way to help with public mistrust of police, and the unfortunate results of mishandled police actions like this one, and that's to actually invest in the police themselves instead of just equipment and buildings. Pay them very well, recruit better candidates, train them very well, and refuse to compromise on expectations for their behavior.
There was a situation very similar to this that went down in another state recently, maybe one of the Carolinas, don't remember. I heard about it briefly on NPR - it didn't cause civic unrest, and there wasn't much in the way of national attention. Why? Because the police acted like police - they did not respond with aggression, relieved the shooting officer of duty, addressed the public about his involvement without making any excuses or casting aspersions on either of the parties, and immediately began a thorough investigation, and when the investigation concluded they charged the officer with voluntary manslaughter. He is currently awaiting trial.
The way to return respect to the police is for them to deserve it. Peace officers who resort to deadly force as a first resort are not deserving of respect. They are no longer peace officers. Comply or die is the language of hostage-takers, of occupying forces, of criminals. Peace officers should not be treading that ground.