Defending her actions is different from absolving her of her actions. It's not about saying that everything she did was "right", because it wasn't, it's about understanding her as a character, empathising with her situation, and understanding how she could have made those mistakes. When you do that with an open-mind and open-heart, you can see that her actions didn't come from a bad place, she wasn't being deliberately deceitful, and that her actions, though misguided, are forgivable.
You can forgive and still want a relationship with her, you can forgive her and not want a relationship with her, you can forgive her and want to be close friends, and you can forgive and not want to be close friends, but it's the people that can't forgive her no matter what that are the problem because to do so lacks empathy and compassion.