Sad that so many turned away and didn't get involved. Obviously the "attacker" didn't have a gun, so the helper wouldn't have been in too much danger of being shot themselves. Even worse was how more females seemed to try doing something like hitting with a purse, flower bouquet, jacket, etc, where most of the men walked off.
And yes, that was a stupid move to make a video like that - how would they have known nobody would have been carrying a knife even? Even if someone was to go in with flying fists to stop the "attacker".... He could have gotten some pretty bad injuries...