It very much matters what happened in the store.
If the police were called to a store because an African American was carrying a weapon walking up and down the isles and they killed because he wasn't responding to their orders, one might think that the shooting was justified.
Now if instead we see an African American in a store picks up a toy gun or a bee bee gun that that store sells and is walking up and down the isles while talking on the phone carrying the gun casually and police enter the store and shoot the man upon site in the back, well, I think most would say that was not justified.
So context does matter, especially if we are to move forward and to create a better more effective police force.
In this particular video and in the context given by walmart or the police, they appear to have acted appropriately.
However, if it turns out this guy was just looking at bikes and road it around a couple of isles and was never spoken to by the staff, then the fact that the police were called is already an issue and the fact that he was arrested is an even bigger problem.
The context matters because that changes the appropriateness of the reactions and it changes how we move forward and how to improve things or address the issues.