Who cares if the CIA has a backdoor? It's still better to encrypt his archives than using plaintext. The chance the CIA might have a backdoor is lower than the chance the CIA might decipher plaintext.

Of course, you'd have to use a non-networked computer for this, in case Truecrypt phones home...

Well, the article didn't say that they were archived in plain text. For what we know, it may have been encrypted with TrueCrypt, and it may be readable by CIA.