I might be blind and just can’t find the privacy control for this, but right now searching for email will point to an account for someone and just guessing the email allowed me to find & follow people. Even exposing the user name might be considered a disclosure, though, and at least in one case I know a person who avoids this sort of thing for personal safety. Where’s the opt-out for people who don’t want to be found via search in the social bits?
The same problem here… Unfortunately, the companies in the modern world do not want to understand that privacy is crucial for their customers - and when there are leakages of personal information of people from these companies, they suddenly panic 
There are some interesting software like Fig Leaf that can be the solution for all this mess, check their blog, very interesting thought on the situation.