@Tinkeringbell Good point, I was assuming to be one of the group. I couldn't imagine walking in on a group to set things straight unless you know them really well (or like a good fight).

I guess the overall goal is to indeed make sure they don't share it because there's no audience for it, so to take their audience away. Maybe empower the nodders into ignoring the guy. I'm fully aware that changing this guy's opinion is not going to happen overnight. But perhaps even just turning the conversation, by: "I really liked her performance today. I've been reading up on her work and she's really an expert in the field." Might convince the others to change perspective.

Alright, I added the 'united-states' tag. The described situation occurred at a tech conference after-hours. I guess it could be 'europe' just the same.

I added that part because understanding why someone acts some way, could help addressing it, but I understand your concern. Thanks! Should I edit it out?