the entire phrase 'opt-in', i think, is being misunderstood here. you opt in to blizzard's use of your personal data when you sign up for a battle.net account, and when you play their games. (_three_ EULAs to accept every patch day!?!?)

that right grants the entity blizzard, or activision blizzard to process your data in the same geographical region. There is no problem from a legal standpoint in Europe as long as personal information isn't being transmitted outside of the region (e.g. from Europe to Americas), or isn't being passed on to third parties without your specific and explicit consent.

it sucks, but legally there's little you can do here. However, I think blizzard should act on more good faith with it's [so far] loyal customer base. Best case here is that people simply stop using the forums.. we lose the one valid way we have of providing feedback on the game we all love. Worse case is people simply cancel their subscriptions, insist on proof of removal of personal details, and move on to a game publisher who isn't going to skirt along boundaries of the law.