My opinion __is not__ that Assange should have refused to help Mannings, Assange is an adult, he can chose to do whatever he wants.
What I'm saying is that Assange should have refused to be accessory to a crime.
Journalists are protected when they receive classified informations, even if obtained illegaly, as long as the journalist didn’t do anything illegal
He knew he was helping with something illegal (at least he should have known) and that by doing it he would lose the kind of protections guaranteed to the press.