That they acknowledged as a mistake, and rectified early on. When you first turned on Buzz, there would have been an option for whether or not you wanted to have your contacts displayed, however I guess it wasn't easy to find. Shortly after releasing Buzz, they made it a lot more obvious (I guess due to user complaints):

http://gmailblog.blogspot.com/2010/02/millions-of-buzz-users... (item # 1)

They are certainly responsive to these issues, however the fact is their approach to privacy was confusing from the start, which is a recipe for disaster.