If that were all there was to this, it would be a clear cut case of self defense.
The whole story paints a much more vague picture. Allegedly and supposedly, someone had fired a gun into a crowd, which caused some people to react, homing in on anyone with a weapon in hand. At some point in one of the videos, you can hear someone say something like "he's the shooter", or "he's not the shooter" before skateboard kid starts smacking him with his board.
Then you have the fact that the kid blind fired into a retreating crowd there towards the end, so...
The way I see it, you have a person who wanted to find an excuse to shoot someone, vs. a group of people who wanted to provide him one. The whole thing is a clusterfuck of fear, misinterpretations, spilled blood, and bullshit.