You say that a crowd of black people should charge several armed police officers? How many black people would be killed, do you think, since the police officers does not stop another police officer from murdering a black person?
Force in numbers is effective- there was no guarantee the cops wouldn't shoot and the crowd stayed, so that shows some level of courage, or whatever- could have been an act of defiance.
Their guns weren't out, they were participating in an excessive force act and video was being recorded by someone in the crowd plus the surveillance cameras across the street- that should have registered with the cops, but apparently, they were too involved in being idiots. They wouldn't need to rush the cops or put their hands on them but there's always something nearby that can be used as a weapon if they really wanted to end the killing. If the store didn't have a gun, baseball bat, axe handle, etc, I would be surprised- if I had a store, I would have something ready because it's just about the only way to survive- convenience stores are robbed and employees & shoppers attacked too often. Well, in America. The White areas aren't immune, either- it happens constantly.
I don't know who put those officers together, but the department needs to take a good, hard look at their people and weed out the bad ones, damned fast. The Federal DOJ is looking into it- that should, theoretically, cause some action.