This is a common argument I have often heard. This is also always an argument which doesn't hold its ground. The fact that someone is ignorant or weak-minded does not mean he / she would deserve anything that that person allows to be done to him / her. She might not have wanted it. This woman seems clueless. I feel pity more than anything for her.
You must realize that the appearance of a person does not reveal whether that person is a terrorist. To say all terrorists look like / are Arabs is pretty close-minded. That said, I do not think that woman is a terrorist.