Notice that it says 'effectively controls access' The Sony root kit meets this definition
(2) No person shall manufacture, import, offer to the public, provide, or otherwise traffic in any technology, product, service, device, component, or part thereof, that--
`(A) is primarily designed or produced for the purpose of circumventing a technological measure that effectively controls access to a work protected under this title;
Notice again that here it is illegal to tell someone how to Remove something that is designed to control access to a work protected under the DCMA. If you read the law you see no exception for rootkits or malware..
Yeah, but it's pretty much implied...
They didn't have to explicitly name rootkits since that is malware and inherrently illegal. Sony did something wrong, not the people who removed it, obviously. But hey, leave it on your computer if you want LOL.