But that's the beauty of a cell organization like CB. Isolated agents scattered around nearly everywhere. You might find one, but since they may only know how to contact one or two others in the entire organization, there's never an idea of how big the organization they belong to really is, much less what it actually is called.

The terrorists were not a tightly guarded secret. Everyone knew where their old abandoned bases had been as soon as they found out who it was. CB has been planning their creation and first public appearances for apparently a century.

Granted, this is a Gundam series, so some suspension of disbelief is required.