I'm aware that I have the same biases as the rest of society. I do my best to recognize them, and, where applicable, to add a small mental counterweight before making decisions. I don't think this always leads to better outcomes, but I do think it's a net positive. And if investors act on similar frameworks, they've probably doomed some companies and saved others. The future is unknowable, and we'll never know what would have happened.
I wish this investor had acted out of a desire to be a better person, or a more successful VC, rather than from fear of a mob. I'm not a fan of mobs. But none of us are immune to cultural biases, and we should second-guess ourselves accordingly.
A simple "Sorry <name>, I cut you off, you were saying?" does wonders and makes it clear to everyone that the next person who should be speaking was the one who got interrupted.