And that is why the current all jump on Facebook campaign is so ridiculous. Google, Apple, Yahoo etc (I am sure there are more) all do this. It is the quid that they get for the quo of making life simple for users.
I personally find it amazing how little effort most people seem to want to make to get to read their email, log in to websites etc., but this is what has become the norm: A single log-in to access all of your on-line profiles and actions. Consequently, I find it hard to support the outrage when one company is found to have then used this feature for some other purpose. As far as I am concerned, this is how the company can provide you with these services for no fee (I won`t say free, because it clearly isn`t).
I also find it hard to get upset when a government agency also has access to data which people have willingly given to a private company, but that clearly marks me out as some-kind of apologist for something or other (apparently) so you should probably ignore everything I write.