Both Lessig and Stallman are smart people. But it turns out they are very idealistic, and unrealistic, in their opinion on DRM and freedom in general.
The values of the Free Software Movement are the freedom to cooperate, and the freedom to have control over your own life. You should be free to control the software in your computer, and you should be free to share it.
The GPL that Stallman wrote (or was the main driving force) doesn't give you the freedom to share. It is an obligation. You replace a freedom with a constraint. It really feels like someone is deciding for you what kind of freedom is good for you. So it's always surprising to see him attack other Open Source licenses (that sometimes give you all rights) in the name of freedom.
Now about DRM, the freedom given to people (restricted rights) is exactly what they paid for. If they want more rights they should pay more money, and if they agree on less rights, they should pay less. That's the very basic reason why renting a DVD is cheaper than buying it. And the market, in other words the consumers, will decide what kind of rights they want. It's just unfortunate that the whole content market is ruled by oligopolies (on movies and on music) and therefore the DRM offers/choices are very scarce. But this has nothing to do with why DRM is good or bad.
the whole point of DRM is to deny your freedom and prevent you from having control over the software you use to access certain data.
When smart people start using stereotypes that means there's something fishy going on. After all the whole GPL relies on copyright laws. And Stallman, as such, is a strong defender of copy rights (copyleft as they call it) and intellectual property. But apparently electronic ways to ensure the rights are always respected are not good. He probably considers that doing this in court is preferrable, even for people who earn no money on what they create (like most GPL devs do).