Isn't there router technology that can sense these repeated requests from the same source that exceed a certain threshold over a period of time and then just stop responding to that address?

It would seem to be a common sense solution for the Tier 1 service providers to implement.

Unfortuately, the attack still consumes bandwidth. The router ends up spending its time dumping trash instead of routing traffic. The good news is that your server isn't pounded; the bad news is that it isn't talking to anyone.

Looks like some of the tier-1's are working on deflecting this at the source already.

http://www.securitypipeline.com/infrastructure/21401041

Here's the complete paragraph, for the record:

Although this all sounds like righteous civil disobedience and a lot of adolescent fun, given how Ashcroft and the DOJ interpret the Constitution these days I would seriously not recommend participation in such shenanigans. Otherwise, the FBI is likely to show up at your door waving copies of the Patriot Act, the Cyber Security Enhancement Act, the Computer Fraud and Abuse Act, and the Economic Espionage Act.

Sounds a little bit different from the excerpt and the spin you placed on it, no?