Given that he failed to actually crack the password it seems like a pretty weak argument that he actually helped.
And IIRC the pentagon papers involved journalists helping to photocopy the documents.
Seems totally fine for a journalist to assist someone that's leaking classified data. They're not the ones committing the crime, the person violating their privileged access is IMO.
If you try to rob a bank but your car breaks down before you get there, so you give up, that's not bank robbery.
You may still be guilty of criminal conspiracy or something but not bank robbery. These are legally technical areas that are more complicated than what you're portraying.
Assange "conspiring" with manning to crack a password is not