So Facebook is evil for letting you get hacked if I am reading this right? So Blizzard is a million times worse ( just the first company with massive hacking problems that came to mind). A company that lets this happen isn't evil, incompentent or too lazy to protect an unused account maybe, but not evil. If they posted your password and details for all to see you may have a point but not for this.
Edit: It is a good organisational tool, better then calling 20 people to organise plans by far. I have never got the complain about people YOU choose to add bit, Facebook doesn't force you to keep friends who post annoying shit, they allow you to hide it as well if you don't want to remove them completely.