My beef with DRM is a bit dependent on which DRM scheme it is, and what company employs it.
Mainly though, DRM doesn't stop piracy. It barely even slows it. This much is proven, it's a completely irrefutable fact. Hence, the only explanation for still using DRM, especially a DRM scheme that is cracked very early, is (as mentioned earlier) that it is not in place to hinder piracy, but to limit a legitimate user's use of the program. This sits very badly with me, as I refuse to pay a company to treat me that way and put extreme limitations on how I may use a program.
Secondly, DRM schemes that are driver based like Securom/Starforce causes a lot of technical issues for many legitimate users, you only need to take a glance at the official Mass Effect forums (to mention one) to see how many people had problems getting the game to run due to the protection. Sure, percentage-wise this might be a low number, but when you're one of the paying customers not getting the game to run due to the DRM, the argument "oh, but that happens to very, very few people" is neither any help nor comfort. And as known, next to no shop will let you return games you can't get to run, nor will most companies who publish them, so essentially the publisher has stolen your money.
Third, EA has a very bad rep. Customer service is difficult and expensive to reach (especially if you live in a small country like I do), and they're not known to be the most cooperative ones either. They are known to drop support for released games rather quickly, and overall just come across as, to put it bluntly, "hostile" to users who get upset when they encounter problems. Coupled with the disdain a lot of gamers have for EA due to their habit of buying out good developers and then shutting them down (Bullfrog and Westwood being the two that stand out the most) plus the crummy quality some of the IPs have taken after EA got their hands on them... Well, I could go on for a while about EA, and I'm far from the biggest hater out there. I've also read some very disturbing stories of how they treat employees and the working conditions they are under (the EAspouse stories). Although supposedly improved now, it does give you a view of a company that will shy from nothing to earn as much money as it can, no matter the cost. Anyway, the point of this part is, it's not just the DRM, but also the company employing it, that matters. If you experience problems with the DRM, it's less of an issue if it's from a company that has a history of being honest, forthcoming, trustworthy and helpful, and EA really doesn't fit that bill in my experience.
I really don't mind transparent DRM, but Securom is anything but transparent, and it's almost as bad as Starforce was, if not already worse (even if it doesn't physically break optical drives like Starforce did; I lost 2 drives to it before I read online that Starforce could cause it). I really think that Stardock's way of doing it is the way forward, however that means commiting to supporting a product long after the sales have died down, and EA, as well as many other companies, just want to release a game in barely working condition, cash in as much as they can while patching only the most serious issues (if even that), then leave the game alone. That is the major challenge for Stardock's view on "DRM" really, getting publishers to commit to long term support, improvements and extra content development that they aren't going to earn much from (in the short term).
Edited for spelling.