Those facts *are* being disputed. The vast majority of material released by WikiLeaks has nothing to do with abuse of power or free speech. Those dumps are enormously broad, and have large numbers of intended and unintended consequences. The motivation here is anything but heroic.

Just consider how WikiLeaks tried its hardest to torpedo Hillary Clinton's campaign (allegedly because of personal animosity toward Clinton by Assange, from when she was Secretary of State). They received a stolen archive of emails from Russian government-backed hackers, and released them slowly over the course of the election campaign in an attempt to keep a steady flow of negative Hillary headlines in the news. That isn't about championing free speech, nor does it resemble ethical journalism.

To call him a hero you have to willfully blind yourself to a great many contradictions.