That depends or her intentions. There are possibilities for this.
Maybe, she just wanted to become powerful, then she'd be wrong, she would be too greedy. Why would she be the only one to deserve the power? Why does she deserve it? Her action wouldn't be justified
Maybe she wanted to save only her people. She would be wrong as well, because she would be selfish. Why only her race deserve to be saved? The other people are not worse than them, and there were other people who also would deserve better oportunities. Her action wouldn't be justified
Maybe she wanted to rule everybody with power. She would be wrong too, she would be starting a dictatorship in which everybody would have to submit to her will and nobody would have rights.
Maybe she just wanted to end the war. Then, she wouldn't be wrong, as she would be fighting for peace for all the people.
In this last case sceneario, we can't judge her by the consequences(like things the way they are now, the juubi unleashing it's anger, people getting a more powerful arsenal to fight with, etc) as she couldn't possibily know what eating the fruit would cause. Of course, she should've known that there was a reason not to eat it and that her actions could have consequences, so she wasn't very smart, but her intentions were not evil. Her actions would be justified.
The thing is, there are 3 scenarios in which her action wouldn't be justified, and only one in which her action would be justified. So, there is 75% of her action not being justified.