So let me get this straight: In America, you can be chased throught the streets by a man with a gun and when you attempt to disarm him to prevent yourself from being shot and killed YOU are in the wrong and deserve to be shot? Wow. Great country.
If you just witnessed someone committing a serious crime, legally in some states you could pursue the subject & attempt a citizens arrest, detain them until police arrive. Provided you, call the police, inform the subject of your intentions.
If, for example, Arbery had just stabbed a guy, dropped the knife & ran, or raped a woman, someone witnessed this happen then chased & tried to detain him, then he attempts to wrestle for the gun, the shooting could well have been justifiable.
But all Arbery was seen doing at that moment was running.
In the Rittenhouse case, had he been an active shooter, spraying bullets & mowing down innocent protesters with
glee, then any member of the public could have taken him out with a bullet to the head & faced no charges, but he wasn't, all the people he shot were attacking him & or attempting to disarm him, having not witnessed him commit a crime.