It's usually not a good idea to rush to judgment. In this case, for example, one of the links you provided already contains a retraction, which reads:

A headline on this summary originally stated that DynCorp "Pimped Out Boys in Afghanistan." While some accounts state that sexual abuse and enslavement are common in the tradition of bacha bazi, there has been no confirmation that the boys hired by DynCorp to dance for Afghan police performed sex acts.

In the other site you linked to, rather than a retraction there is now a link to a followup story which explains the other side of the story. Some employees were throwing a going away party and hired a popular teenage performer. When management caught wind of it, they cancelled the event and fired those responsible for organizing it. Thus, the event was not a bacha bazi party for Afghan Cops, it was not hosted by a US contractor, and it didn't even occur.

It sounds to me like the state department and media did the right thing here initially. They investigated the allegations and performed legitimate fact checking instead of running with a story that sounded juicy and sensational but turned out to be much ado about nothing.