He's also not a journalist by traditional definitions i.e. no formal training, no accreditation, no redaction to protect innocent parties, no protection of sources.
> WikiLeaks wins top Australian journalism prize... The Walkley Award is one of a number of journalism prizes won by WikiLeaks in recent years, including Amnesty International’s UK Media Award and the acclaimed Martha Gellhorn Prize. The latter award is given to journalists who reveal “an unpalatable truth that exposes establishment propaganda.” These prizes undermine the Obama administration’s claims that Assange is not a journalist and that the publication of thousands of secret US diplomatic and military cables is illegal.
He's more akin to an activist.