I don't think she was pushing you to be angry with her.
I think she suspected that you had been angry with her, but had moved past it, and she wanted to revisit the time when you were angry. She was saying that feeling angry would be completely understandable - as understandable as someone needing to cancel because things come up.

If you are like me, you might move on to a place of understanding, and deny there was ever any anger there initially. That's one of the hard things about therapy, getting to a better place - because we do have to go on with your daily lives - then stepping back and revisiting the place we moved from.

I think she was just trying to help you explore all of your feelings about the cancelling and the lack of response to your email.