Maybe she will take on your constructive criticism later. Perhaps she had a bad day? Don’t know…I sympathize a little with her. Sometimes hearing your faults is hard, but let’s face it she did ask for your feedback. I honestly think you’re amazing for giving people feedback like this and working with writers and you should be charging for it. I hope she reads back through your feedback and makes some changes. I actually had a similar interaction with a friend recently who said her work was terrible and asked for feedback. I told her how to improve it and said it’s not terrible but I would cut it in half and she then proceeded to tell me how she could never cut any of it. It’s kind of the same. Except I just left it after that. I think people sometimes ask for feedback that they don’t want.