YMMV
Believing things simply because supposed experts say them is a well-known logical fallacy. So the people were right to be skeptical. He also contradicts himself as shown, there is no reason to listen to him on this topic to begin with. The tale is utterly confused. There may well have been people in that audience who knew more about dolphins than he did. "The data is easy to interpret" is a sentence I've heard from idiots so many times, that's Dunning-Kruger in full force. Dumb people generally assume the world is easy to understand and they have it all figured out. Who in the world would think intelligence is a field that we know everything about and there can't be any further debate.