You misunderstand.  I did not mean all bitcoins, just the ones they are in possession of from the silk road bust.

They probably cannot access them due to encryption or passwords or whatever, on the media they possess and so they announce they are forfeiting the coins, as if its a choice they made.

Like a thief who cannot break into a safe, "forfeiting" the contents.  The thief just dumps the whole safe into the ocean.