About five years ago, I saw a video where a professor at Stanford University said that after developing his first MOOC he realised that his previous 28 years of "teaching by lecture" had been ineffective. (I think he said "a waste of time" or something similar.)
The professor was talking about what he had learned as a result of using the "Flipped Classroom" - teaching method where students study "the material" on their own before they meet in a classroom. The classroom session is used to discuss "the material" - no lecturing.
Sorry but I could not locate the original video, but here is a 57 Second extract from a 1 hour video produced by the same group at Stanford.
My Stanford MOOC experience in 2012 and 2013 (organisational analysis & databases) caused me to research the question "What is learning". After several years of research, I have concluded that "learning" is just a name for the process of "creating new synaptic links in your brain".
Furthermore, the learning process may require that you have to actively suppress "old" synaptic links that could be said to represent "Fake knowledge".
So, my working hypotheses are:
(1) The popular belief that:
"Long lectures (whether supported by PowerPoint or not) are effective in helping people to learn."
is false - in today's terminology this belief is fake knowledge
(2) Learning requires action - passive listening is not effective.
If my hypotheses are true, then a lot of today's "PowerPoint lecturers" are going to have to go back and study modern pedagogical practices so that they flip their thinking before they flip their classrooms.
So my answer to the question about the "upset professor" is "Send her back to (modern) pedagogy school!"
As a milder social response, you could try to engage her in an open discussion about pedagogy.