He is not a Russian agent, that is a disinformation campaign akin to tarring and feathering so the person has a lasting symbol of the judgment against them they cannot wash off. Functionally speaking, he is quite close to the role of journalists in wanting to know secrets and to publish what they learned from others privy to the information. There is well-established legal precedent to allow this because people understand the greatest risk to their freedom is in a closed system ruled by the state, where people cannot speak out about wrongdoing they may learn of, if it is labeled as secret knowledge for which they can be punished. This is how tyrants maintain control by silencing critics.
He differs from journalists, in most cases, by being more concerned about the broad need of humanity than for a narrow view of political party or nation-state, for that matter. This makes him puzzling to many who are very attuned to their pedigree and their alliance with their fellows and do not see the big picture at all. They are typically working with an agenda to serve a particular perspective and will shy away from unpleasantness that hurts their preferred cause or group.
Assange is much more revenue neutral. He has a deep distrust and distaste for all big government operations and has a keen intuitive awareness that all that is happening is sinister and has many negative consequences people are unaware of currently. These, he is attempting to bring forward by his exposés to show the dark underside where damage occurs by the acts of government, not just through military might, but in many ways they interact with other nations and cause harm of all kinds. He is a would-be righter of wrongs. If he makes mistakes, this is quite subjective and will be difficult to be certain one is not simply reacting to one’s own biases because he is quite evenhanded in his actions and not playing favorites. We see him as an asset supporting divine truth in the end.