WikiLeaks film shifts focus after Julian Assange won't share info
At one point, Manning, explaining to Lamo why he was leaking information that called into question the morality of the Afghan and Iraq wars, types the phrase, "I... care?"

PHOTOS: Cannes Film Festival 2013

"It seems to me both so enigmatic but so important," Gibney said. "He uses a question mark, not an exclamation point, so it's shy.... It testifies fundamentally to his commitment."

After the movie, being released by Focus World, premiered at the Sundance Film Festival in January, Assange supporters denounced it on Twitter using a hashtag with an epithet and Gibney's name. "For [Assange's supporters] it's all about white and black, about propaganda," Gibney said. "There is only one truth, the truth that Julian tells us. And there can be no dissent. It's not so dissimilar from Julian's enemies."

Today Assange and Manning reside in jails of a type. Assange lives in the Ecuadoran Embassy in London, where he has sought asylum from extradition to Sweden. Manning has spent more than three years in various military prisons awaiting his June trial.

"People say my films are political," Gibney said. "Maybe they're political. They're about moral quandaries. I'm interested in human psychology ... how people handle power, what motivates people to do what they do."