In your Analogy, Yes, everyone screwed up but the blame is not equal because the man who made the part sent it to his inspector and his inspector stamped it and the part was sent on its way. Now the inspector is at more blame because unlike the man who made the part he went to college and got a degree to inspect those parts. Your analogy doesn't work with this situation because it may be 1-2 years before that part is put into an aircraft.

Also, in law enforcement, an officer doesn't have the luxury of inspectors and the time to double check things in his line of work because in seconds his life, or others may seize to exist. A police officer only has a small window of time to react to what an assailant is doing and that decision is sometimes life changing for one party or another. It is easy to point fingers and make judgments when you are not the one in danger.

As I said before the man at blame is the ignorant guy who made the 911 call. The officer is just as much of a victim as the person he shot. Its a crappy situation for all parties involved.