Clearly you haven't watched a lot of racing or are not familiar with the skills and abilities of an experienced driver like Tony Stewart. While there is no way Tony intended to hit the young man, witness accounts and the circumstances of the incident suggest he purposely made an aggressive and negligent move that while not intended to hurt anyone, was the main factor in his death. These situations happen all the time and are predictable to the driver who dumps an opponent into the fence. While I've never seen one end like this I'll bet there have been close calls that we'll be hearing about.
Given his experience and talent level one could suggest Tony either knew, or should have anticipated the other driver would approach his car. If in fact he did what people are saying he made a tragic mistake despite the actions of the other driver. Trying to scare the other guy rather than avoiding him may have looked like a split second decision to you and me, but that's because we're not an elite driver in NASCAR and multiple other racing divisions. I'm not anti Tony Stewart in any way but suggesting anyone who might find him at fault here is unreasonable speaks to a degree of naivety (kindly phrased) on this subject.