I would guess the "heady" types of individual would be like that because they have many things on their mind they are thinking about so they want to be efficient with translating their thoughts to others.
I'm also reluctant to say anything because I myself have asked questions about the "obvious" and been totally embarrassed over it. Usually in the setting where I don't have time to feel (hands on) my way through a problem or system and need to ask something right away. Hateful...
You just need to phrase the question differently and utilize your abilities to rapidly process information. There is NOTHING wrong with starting a discussion with something like "I'm behind the curve on this so bring me up to speed...". Then ask all the obvious questions you want.
Never underestimate the power of stupid people in large groups