I am, overall, against any form of government regulation of relationships between consensual adults.
I believe that each network operator should be allowed to set it's own policies, and should suffer or benefit from the results of those policies. After all, it's their money.
They may make stupid decision -- many people do. But that doesn't require government intervention, it requires market intervention in the form of customers choosing alternative providers.
A good technical example is
VoIP traffic. VoIP requires a higher level of
QoS than web traffic or e-mail traffic. This raises the initial cost of infrastructure and also raises the cost of maintaining the infrastructure to a higher quality level. It is only reasonable to charge more for services which cost more to deliver.
Alternatively, that AT&T argument was horrible. Whoever wrote that document should be taken to the e-woodshed. That document is sure to encourage government regulation, because it does not clearly define AT&T's plans for future pricing. It raises the boogeyman of future issues, which is exactly what AT&T's opponents want.