Earlier quoted context omitted.
I think it was really valuable to surface the feelings of the person who was the target of this discussion. It changes the perspective of the incident.
In what way? Sure, it's an additional perspective, but it sounds like you're suggesting it should somehow alter the audience perspective.
e.g. Mam, you tell me if I got this correctly. This is how I think it works...
I think it is actually a position of submission in a discussion, the person who is doing the talking is accepting the higher authority of person doing the listening to find errors in your understanding of the subject.
You explain to see if you got it correctly in front of a teacher.
The audiences would have been better served by hearing from the expert directly, so the moderator clearly failed at moderating. There is a chance that he may not have been sexist, but more student like and in the flow of events forgot the place, audience and his role in the conversation.
I didn't see the video so just exploring possibilities.
The audience may have come to thank the person who yelled "LET HER SPEAK PLEASE" for two reasons...
1. They thought moderator was sexist and one doing yelling was a liberator.
2. They wanted to hear the expert. Moderator was doing a poor job at moderating. This was not classroom. The people were there to hear the experts, they probably paid to attend the event. So, "HER" in this case is referencing the expert, not a woman. e.g. a version of "LET THE PROFESSOR SPEAK PLEASE".