It's probably just like the restrictions announced before every NFL telecast. I'm betting that the AIPAC proceedings may be subject to copyright restrictions on reproduction and distribution.
It may be that Google is doing censorship; more likely, they're just trying to do the same thing FR does, with regard to restricted sources.
Given Google’s history, I think you’re being far too charitable.
Copyright does not exist until a work has been rendered into tangible form. Something like a play exists in tangible form before it is performed, and thus taping a performance would violate the copyright of the pre-existing work. An audience recording of a completely improvised performance, however, would not seem to violate copyright since the work didn't exist before it was recorded.