Because Kyle is great on the restarts, and until Stewart got hot, Kyle was at least tied for most wins.
He also like it or not, is a living drama. Kyle verses Harvick at Darlington, Kyle verses Papa Childress, Kyle verses Texas (not sure Mars suffered w/Texas, they actually got good press imo).
If you took a newbie or youngster to a race, and realized they were unable to follow the events in real time, just tell them to watch everything around the 18 car, he will be close to most of the big events.
Like Dale Sr., he is a big catalyst, and he owns the most love/hate.
Even compared to Stewart it is no brainier, until mid September his biggest 2011 moments was the Vickers/Sonoma incident, and the Lewis Hamilton gig.