Did you ask them what was confusing and how it would slow them down. Did they tell you? Because ultimately if I'd hear that without anything to help me improve it's a bit of a catch-all "we don't know so out you go" kind of thing.

This sounds like a pretty douchy sort of "yeah you're just not good enough, look how fast we are" jab by them.

Better not answer with "Thank you very much. I also had a feeling that some people in the room lacked the mental capacity to follow my explanation."

;)

Reading this thread makes me want to cry. The world is filled with morons.