Ohio is an open carry state. It would have been legal for Crawford to have carried a loaded weapon around Walmart, but he did not do that. He picked up a bb gun and someone got scared and erroneously called the police that there was a shooter in Walmart, which was not true.
The police arrived and instead of assessing the situation, killed Crawford who had no idea and no reason to know that he was suspected of being a shooter in Walmart. Because Crawford had no idea and no reason to know he was under any kind of suspicion, he was not as quick to assess his own situation as the police, quickly mis-assessing the situation--were to kill him.
How often do you suspect that people in Ohio walk around department stores with a gun that looks like that in their hand? We aren't talking standing there in the bb gun aisle next to the box, inspecting it for a few minutes, but rather roaming around the store for 20 minutes with the gun. Unless the answer is "somewhat often" to "all the time", then the open carry law is irrelevant to the other shoppers' reaction, and largely irrelevant to the cops' state of mind when the enter the situation.
IT is extremely reckless for Walmart to sell such deadly looking bb guns in the first place, let alone to have them sitting on the shelf for anyone to grab and take out of the box. If on a jury I'd find them culpable for many millions in damages, and convict their CEOs of involuntary manslaughter.
This case also shows the absurdity of open carry laws and the unreasonable position it places cops if people were actually doing what the law allows and just waltzing around public places with assault rifles in their hand, far from any legal shooting range.
However, unless a shopper was acutely aware that Walmart sold such a gun, the perfectly rational response to seeing someone walking around the store with it is "That guy (not "boy" but very full grown man who looks old for his age of 22) is about to go on a killing spree!" That would be the reasonable fear no matter his race and whether he was age 15 to 90.
When the cops get a "Guy walking around with an assault rifle at Walmart" call and they walk in and see just that, their rational response to presume the guy is a deadly threat. The fact that in hypothetical theory a person could legally do what he is doing, even though no one ever does, wouldn't enter into it. It is this that makes the callers and the cops not look racist, but at the same time makes Walmart liable and the open carry law recklessly dangerous.