Both ways the bonehead holds the gun certainly could cause a problem for a clean defense (holding it down and back at his side, and holding it up near his ear…that one perplexes me but what do you expect when all his education is from tv or other boneheads?)
Added to that, he is pushing the intended victim with his non-gun hand. At Colorado Krav Maga, we train on these types of scenarios all the time and as you can see by the video even the other kids instinctive response ended up working well. I think the lessons to take away from this video is timing. When is go time? He could have been shot numerous times before he acted, but perhaps he didn’t feel like it was imminent. He may have known his attacker (likely), so there was bound to be some banter or even monologuing going on.
When reading the boneheads body language, I think its apparent that had the intended victim just took off running away (beyond his first move back to his skateboard) the bonehead would likely have just started shooting, like a dog that only chases a cat once it starts running. It’s obvious in this video that the boneheads only source of manliness was the gun (and it wasn’t very big). They guy was a complete wimpy looser and got beat down by a smaller skater dude, how embarrassing for him.