We can't defend everyone's morality equally. Most of us agree about the immorality of racist laws or forced sterilization. There just isn't the same kind of consensus about the morality of publishing leaked classified documents.
It may be, she's doing her small part to change something in the future. Her actions will be remembered. They already are by many people. And it's a bit myopic to just focus on "contempt of court" part.
Everytime Manning comes up, it just reminds me that US is still murdering people around the world without any justification or verification of who was killed in most cases, while the system is focussing on punishing her further - instead of trying to improve and save innocent lives.
I bet that to disclose hideous crimes would be unanimously seen as a morally acceptable act by the majority of the people.
The problem is not in the leaking act itself, the problem is the contents of the leaks.