Much ado about nothing.
To my knowledge, zero suits have been brought involving the breaking of encryption on DVDs and Blu-Rays. So the affirmative defense under fair use doctrine has never been tested in court as it bears on breaking encryption. The fair use defense is still available. If the MPAA did bring such a suit, it's quite possible they would lose. Which may have something to do with the fact that the specific provision in the the DMCA has never been tested in court.
Do not confuse the above with the Betamax test case (which was won, BTW), allowing time shifting under fair use. And do not confuse this with recent suits involving file sharing. (Look up Capitol v. Thomas. The defendant lost).
If you're breaking encryption for the purpose of playing legally owned content on some device you own, and are not distributing it, well, don't worry about it. It's unlikely in the extreme the cops are gonna bust down your door and cuff you for it. Especially if you don't shout it from the rooftops. Just an observation, and not legal advice.