DRM is an evil, evil piece of software no matter what its use is in my opinion. You're putting something on MY computer that you didn't tell me about, and you're trying to hide it by giving it root admin access. That almost screams criminal to me.
I'm not sure it's required to give root access, myself, and I think it's probably done as the lazy solution quite often.
I have a double-sided view of DRM. It does piss me off, and I try to avoid it where possible, but it isn't the case that its existence is totally unjustifiable. If DRM was limited purely to ensuring that you, the user, had a legit copy of the disk it'd be fine. It's when they add in s### like limited activations or always online requirements that the problems start - and AFAIK this stuff is more about removing the second-hand sales market than it is about actual copy protection.