I mean, if I'm in a banana republic like Argentina, sure, I expect to get two bullets to the head and thrown in the middle of the ocean... In America, I expect more professionalism... obviously, again, this is all speculation. If the kid motioned like he was going to pull a gun or something like that, I can see the officer falling for it. That's why details matter.
IMO, the protests are fueled up because the initial reaction from the Police was absolutely stupid. Showing up with army gear, aiming at protesters, taking forever to even release a statement. Then they release that video that, in reality, has nothing to do with the kid's death/murder. There was clear distrust before the incident, and this whole thing just tipped the scale.
I'm with you as far as cops... I grew up in a country chock full of dirty cops. Even after moving to America, just can't shake the disgust...