There's a reason that people say corporations own us, or corporations own the law. In some cases, acts that might result in lowered profits are punished worse than murder.
Being a Canadian, I really should look this up. That being said, I try to avoid situations where I would want to break a digital lock. There are plenty of alternatives encumbered media, provided that you don't have your heart set on a particular product. For example, many publishers offer unencumbered ebooks. Library books do have DRM, but it is pretty much a given that some sort of access control is needed since the books are on loan.
In practice, though, the real source of this stuff is the WIPO Copyright Treaty, wherein 116 countries around the world agreed to adopt similar laws on this topic. Those "one-world government" conspiracy theorists have a point!
Source? I wouldn't have thought a US law saying these things would be allowed.
https://www.eff.org/press/releases/eff-asks-appeals-court-ru...
The courts that handled the DeCSS cases (code that broke DVD encryption) allowed that code like DeCSS was speech protected by the First Amendment, but basically ruled that the functional aspect of the code meant it gets lesser protection. Posting the code, but even just linking to somewhere else it could be found, were both found to violate the DMCA, and that restriction was found to be permitted by the First Amendment.