No of course the police are not 100% honest, just like 100% of the population are not.
BUT like most of society, the vast majority of officers ARE honest.
For me it boils down to this. If I were in the officer's shoes. I'd been told that I'm doing a hard stop on a known gangster who is likely to be armed.
I then have to actually do this and face down a guy who may at any moment shoot me or my fellow colleagues (and likely friends).
I'm given only a split second to decide if he is a threat or not. A split second to make a life & death decision.
Would I be unreasonable to shoot if he raised his hands quickly with an object in his hand that could possibly be a gun but I've only had maybe 0.5 seconds to decide? Oh and he's probably stood a distance away too. Oh and if i take a couple of seconds to actually double check, he could have shot my colleague or worse still myself.
Every officer knows that if they shoot and kill someone, everybody is going to be crawling over your split second decision with a fine tooth comb for months, if not years. Your life will be upside down, not to mention the psychological trauma of having to take someone's life for what may turn out to be a mistake.
In that situation, can anyone hand on heart say the police officer MURDERED (ie. premeditated) Mark Duggan? I'd say you were an idiot for thinking that and encourage you to go back to UFO and 9/11 conspiracies.
Was a mistake made? Yes. Could they have done things better? YES.
Was it murder? No.