my thinking is, everyone keeps things private. its fairly probable that there is as much damning info on most other orgs. in the context of wikileaks role in the 2016 election, im sure the RNC would look just as bad if they had all their dirty laundry aired. to my mind, you must consider the consequences and context when leaking, and for that reason i think wikileaks was highly unethical and they are partially culpable. there is no way assange wasnt aware of the motivations behind the leaks. so, to me, he hasn't been impartial- its a sin of inaction, not action.
a third, and minor point- when assange was last interviewed on bill maher, he struck me as very careful with his words, and very talking point ish. sounded just like a politician. wouldn't give any play to bill's questions about putting thumb on the scale for trump. not much there, but weird for someone who purports to be even minded, rational, fair and pure to behave like that.