I think that the Q&A session (question and answer) session at the Berkshire Hathaway annual meeting is very famous because Buffett and Munger (investment geniuses) answer all questions asked of them. I think the sentence means that even though there is a lot of hype/frenzy about the Q&A session, it is really Buffett and Munger themselves that get the most attention.

I think John's answer describes the meaning of the paragraph as a whole, but this seems quite clear anyway. Regarding the first sentence, you are right to be puzzled, it is a non sequitur. I would expect furore and importance to be in direct proportion to each other, but the logic of the sentence seems to be predicated on an inverse relationship. The following versions eliminate the contradiction, so they make sense: With all the furore about the Q&A, you might be forgiven for thinking it was of greater importance. With the lack of furore about the Q&A, you might be forgiven for thinking it was of lesser importance. ..however I'm not sure either of them fits what the writer was clearly trying to say, so I think this is more than a mere language error; they simply seem to have been a bit confused when writing it.