You honestly think somebody who has been around camera's and audiences all his working life has so little composure and presence of self that he just decides to wander on stage of a live performance infront of all his peers and esteemed colleagues as well as being watched by millions and assault the presenter in the most lame fashion ever?
Give the man some credit, he didn't get to where he is today by acting that impulsively and recklessly.
It was a deliberate act to give a bit of notoriety to the Oscars, raise both Will Smith's and Chris Rock's profile (they're aging 20th century icons), and act as a talking point so people are interested in the Oscars again, which frankly if things like this didn't happen would be boring and people wouldn't watch.