In essence, it says that the major-major stars are enjoying special protection by the IAAF and will not be allowed to test positive. This protection, though, is of limited duration (the article suggests 8 years) and if these athletes hang around too long, the IAAF will eventually let them go - hence the positive tests by Merlene Ottey, Javier Sotomayor and Linford Christie coming late in their careers. Marion Jones' recent positive is also an example of that - according to the author she must have been framed, since it makes no sense for a sprinter to use EPO.
Disclaimer: I'm not suggesting any of this makes sense, merely presenting one point of view I came across. If you disagree, don't debate with me.