On the other hand Dave has a notoriously thin skin. He is very good at criticizing everyone else but he absolutely doesn't take criticism himself. Only time you are going to strike up a conversation with him is if you agree with him on everything. He generally expects everyone to bow to him as the inventor of blogging and RSS and podcasting and whatever, and that means you are supposed to listen to his opinions on everything, agree with him, and see his wisdom and if you dont, YOUR BLOCKED, cut off, dismissed and ignored.
Who knows how that meeting with Marissa Mayer actually went down but there are plenty of people who have been lectured, scolded and demeaned by Dave who have probably wanted to walk out on him so its entirely beleivable that she did and he probably provoked at least some of it.
You would think Dave would, after all these years, realize that if you post stuff on the Internets people are going to flame you for it because A. They disagree B. They troll for fun C. Dave has ticked off so many people over the years they flame him because they are perma-tired of his holier than thou attitude.
No people shouldn't be rude, ever, but they are. Dave is rude all of the time too. Yea you can just like, you know, block the entire Internet and that will stop it, but at what price. I think Dave is mostly pushing for the latter, or at least he wants anyone who doesn't agree with Dave on everything to be blocked permenently from everything.
Dave, if you want, to block everyone on the Internet who disagrees with you, fine, go for it, write your own tools to do it, but don't expect everyone else to do it for you.