Actually, it's because hurting a pretty, white, quasi-middle-class boy who's participating in an 'all-american pastime' doesn't read so well in the press.
The people I get are not racers. I can drive across sand better in my '91 Ford Escort Station wagon then some of these guys in their shiny toys.
The police do not want the lawsuits from the family especially since until the Police give chase no one is in imminent danger, unlike someone running a red light in the OC.