DDOS: Who pays the price?

There's an interesting post on Kuro5hin this week, in which simul recounts his experience with the FBI over recent Distributed Denial of Service attacks. The FBI, of course, is after the pimply faced teenager responsible for the lost revenue and increased ISP traffic charges, but as the author points out in his response to the FBI, the government should perhaps look instead at the service providers, who are unflinchingly charging the victims of these crimes and not doing anything to prevent their own networks from doing harm? As Simul points out,

So why haven't ISP's implemented endpoint egress filters? The problem with DDOS security is this: if you implement DDOS security, it does not protect your network, it merely prevents your network from harming others. Why would an ISP spend extra time and effort implementing a security protocol that was good for everyone else... but not for them?

So it's actually good business to do unto your neighbor?