Why does the NFL get a free pass on doping?

(from the International Herald Tribune) This was originally published in IHT just before the 2008 Super Bowl, and it is a good question to be asking at any time. It mentions Shawne Merriman (who, like fellow Charger Luis Castillo served a recent NFL suspension for steroid use), and questions distaff policies on punishment with the NFL and MLB, and huge differences in media attention to the two. [link]