I don't understand this reasoning. If I am a witness to a murder the cops don't ask me to prove that the victim also murdered someone. As long as the murder I am talking about is real, that's all it matters for the specific case.
We have no idea about any other leak they might have, we don't know if they have RNC material. That doesn't mean that the DNC leaks, or today's CIA leaks, are of any less gravity.
Bad analogy. Wikileaks doesn't witness any crime. They just report what the witnesses claimed that happen.
My point is that Wikileaks withholds information. They are releasing certain information to make some people look more favorable than others.
Wikileaks can get CIA secrets but can't get something as simple as Trump's tax returns. lol!