It's generally a good idea for leakers to be selective about their releases (Snowden did a better job than Manning in that area IMO). I guess Wikileaks is between a rock and a hard place, because if they started editorializing then that would lead to political bias.
Has anyone leaked something about Russia that was then denied by Wikileaks? It could be that the US has a more active community of investigative journalists.
Well, since it was years ago, it's possible that they have reversed course since then. They disappointed me a lot, and I didn't keep up with them after that...
Political bias? Like when Wikileaks supported researching the Pizzagate conspiracy during the 2016 US election and posted links to /r/The_Donald "investigation" threads?