It's not that simple, TC. The DMCA allows the copyright holder to regulate how you'll use the copyrighted material. So, a DVD may force your play to display advertising before a movie. Circumventing this would be a crime, due to the anti-circumvention provisions of the DMCA. Now, what legitimate this right to make such act of circumvention illegal? The concept that, since you have to copy digital media into some form of memory, the copyright-holder can regulate it.
Also, you can make a single backup copy, but you can't circumvent the anti-copy protection with any cracks or outside material. Why? While you can, yourself, crack a program in order to make a legal backup copy, the tools (ie, cracks) are illegal tools. So unless you are a cracker, you can't make backup copies if they have a copy-protection that is a little harder than usual.