Self-causing DDoS?
I'd think that it isn't so much a DDoS attack as its just a bunch of people trying to grab the data and are just overloading the servers in the process. From my experience with government websites, I'd think that they were built around the concept that very few people actually read up on government affairs (politicians, law school students, journalists, and other sad-sacks that got saddled with reading through records of government proceedings...)