Gerald, you make a valid argument. However, unless this person was known by the cops on scene prior to running his information how would they know his past? without the reasonable suspicion, they cannot obtain his information unless he offers it. as there is no need to identify yourself unless you are being "lawfully detained", they made an assumption based on his appearance. so, unless they knew him from a prior contact, your argument does not stand for a "just cause" for their behavior. 

further, the other video that is out there actually shows that the window he was "supposedly" reaching through was actually rolled up making it impossible to reach through. 

the fact the officer (shooter) is being charged criminally for her actions, says a lot as well. they were in the wrong and should be held accountable.