I understand what you are saying, certainly every woman on Earth has experienced "mansplaining", and I realize that many "pale faces" act superior, but I wonder in this particular case with Sandra if it was more a matter of age. She is 78, and although you are educated, you are so much younger, and she may have had difficulty in realizing that a young person could have knowledge equivalent to hers on the topics you discussed. Not making excuses for her, it's just something I have noticed when talking with people who are decades older than me.