In his "60 Minutes" interview, Assange acknowledged that governments and corporations have privacy rights as well. His position is that Wikileaks provides a way for whistle-blowers to publicize information that they feel is being ignored or suppressed by the authorities within the organization.
In other words, he describes Wikileaks as a last-resort channel for addressing institutional wrong-doing.
This is exactly the same rationale for why the U.S. government doesn't want their secret diplomatic cables published.