They are not randomly stopping people. As in the example of your situation, there was, I am sure, specific and articulable facts that led them to believe that closer scrutiny should be given to you.
Yes, but many people, I suspect a few here, would get indignant over such a thing.
None of us were there and to speculate at the events leading up to the shooting is a disservice to all involved.
Thus why I said "Now, I was not there and am partially making that point as discussion."