I'm no lawyer, but while circumventing encyption is a violating of current laws, you could make the case that those laws violate the older Home Recording Act. Fair Use is our right, and IMOHO "legal" and "honest" are no longer the same thing. The industry is using it's considerable money & influence to erode many of our rights, including our rights to privacy and against illegal search & seizure.
No offense, but I believe it's
completely about fair use and greedy corporations that are trying to screw us out of something that's been established as our right. And whether or not it will be illegal to decrypt encrypted data is something that remains to be seen- as far as I know, there's only a preliminary injuction while a court determines this. I don't think there's been many litmus tests of that section of the Digital Millenium Copyright Act. I could be wrong, though. Stuff changes very quickly.
Again, though, there are lawyers who can't agree on the ramifications of the HRA and the DMCA. So I guess I'm not going to make any more authoratative statement!