Is this true? If this is the case, how has this gone on without mention by the press

it means that

The regulations of WBO.

"When a Champion must make a mandatory defense, the Mandatory Challenger shall be the highest classified available boxer who, in the judgment of the World Championship Committee, best satisfies the following criteria:

1) has a record acceptable to the World Championship Committee, and who, because of accomplishment and achievement, is recognized by the World Championship Committee as a class boxer; and

2) Complies with the WBO and Association of Boxing Commissions Criteria for the Ratings of Professional Boxers; and

3) In the event that the Champion has a contract with a major television network (HBO, SHOWTIME, ZDF, Sky or other similar broadcast company), is an acceptable challenger to the Champion’s television network."

Nr. 3) explains everything. The fighter has to be acceptable to the television network. Very often Calzaghe and Warren can just go ahead and say that the opponent is not acceptable.

And very often WBO rank a fighter with no big TV-promotion behind him as mandatory challenger. They do that to satisfy promotors like Warren and the big German promotors, because Warren and the Germans feed WBO with the majority of money from the sanctioning fees. The rules have been created to satisfy the big promotors, so they can do whatever they like.

In the case of Calzaghe it means, that he can fight bums whenever he likes. In the case of Kessler (WBA and WBC) it means that he has to fight tough guys like Andrade, who was mandatory challenger.

So that why Calzaghe drops his IBF-belt