"She is perfectly nice. Maybe too nice. I just don't like her." He really didn't need much more of a reason then that, did he?
No Azkaban then? So, she was certifiably insane on her own. "She was a creative outlet? Now that is interesting." Albus ducked his head to think about it. Perhaps evil to that extent was a little much for him. But he could understand it, if he thought about it enough.
Why should she teach him? Because he was Harry's son and what a way to get back at him for the things he had done to her master! He did not think he needed to explain that, and he really didn't think he could use those terms. He was still too thoughtful a person. "Because, it will be fun."