I agree with Blizzard on this, i do think there could be made a drm that prevents piracy, but at what cost both in terms of development costs and at the risk of aggrivating your customers.
The drm and court battle to prevent piracy is a losing one. I think many people dont like bullies and bad guys, with the attitude of the entertaiment industry have against piracy the entertainment industry comes off as the bad guys.
I think of piracy a bit like this. You have a rich farmer that loses one of his seed off his wagon on the way to market, a poor farmer finds the lost seed and plants it to feed his family, should the rich farmer drag the poor farmer to court so he get even richer and if he do, who do you feel for, the rich farmer or the poor one. This is the dilemma that faces the entertainment industry, they must find a way to make people want to pay for the things they make, not bend their arm forcing them to pay.