Central banks hate bitcoin. They hate it because it doesn't allow them to loot bank accounts (Cyprus) and control the movement of capital around the globe. Bitcoin, in fact, threatens the very foundation of monetary control that underlies all the corrupt governments of the world. As such, bitcoin is a huge threat to the status quo, making it an obvious target for the globalists to attempt to destroy.
Discrediting bitcoin isn't enough, however. To really be effective, they need to make bitcoin illegal.