There's a memo that's gone around that incited this stuff. In it, participants are urged to bring in questions that have been written for them, yell at the speaker, and disrupt any effort to answer the questions.
I'm actually quite in favor of political activism, but this isn't conversation -- it's intimidation.
I don't have a lot to add to the story, but I'd like to point out the stark contrast between this and another recent story about a "protest."
PZ Myers plans a trip to the creationism museum with around 200 fans. The museum fears a disruption, and PZ responds to their concerns by writing a very stern message to all participants:
You will not be disruptive. This is an information gathering mission that will make you a better informed individual to criticize bad ideas. Do not interfere with other visitors' ability to examine the place. Ask questions only where appropriate. Collect questions that you can ask of any of the real scientists who will be in our group. Do not get into loud arguments. If a discussion starts getting angry on either side I want you to be the ones to back off.
Remember, if you are calm, civil, and well-behaved, and you tour the "museum", we win. If you are calm, civil, and well-behaved, and the security guards throw you out because they don't like the fact that you're an atheist, we win. If you are angry, rude, and cause trouble that gives them a reasonable excuse to throw you out, we lose, and I will be very pissed off at you.
I think the difference speaks for itself.