You forget that this was investigated and it was all good for the officer. Why do you claim he was shot because he had a cellphone.
Because the video shows that he was shot because he was recording the attack.
He was shot because he attacked the police officer! You weren't part of the investigation were you? They have much more information than you do.
He didn't attack the cop, the cop attacked him. He defended against the attack, which the cop was fully in control of, yet still decided to kill.
It's simply murder.
Why do you want a society where armed thugs can murder people on the slightest provocation?