> why should we believe him and not believe all the various people who have said the opposite?

because he might actually know? it was his organization that received the documents, after all.

is he lying about it? possibly, but what incentive does he have to lie about it?

was he deceived himself? possibly, but if that's the rabbit hole you're going down than what would establish confidence that _any_ claim on this subject is a truthful one?

because the various people claiming the opposite have a clear political agenda that is consistent with the narrative they have been aggressively promulgating through a complicit media? Assange isn't the one trying to start a new cold war. the Clinton faction of the state department and the CIA on the other hand...