Though she appreciated him trying to be kind, she knew that wasn't the full truth. It would be too easy to blame brainwashing and potions on what happened to her to change her from the girl she once was. People changed. Sometimes it was as simple as that. When they got older and life became more difficult with its constant adversities and challenges, people were changed. It was ridiculous to assume that she would be the same person she was when she was in school. Even Harry would understand that growing up wasn't always a seamless process. His life was over too early and he'd faced enough changes himself. Some of the blame could be dropped at the feet of her memory charms, the potions, and even Antonin's efforts at reprogramming her thinking to be more favorable to the regime. Some of it. Not all.