No, that is how our system is set up in order to ensure our users are properly verified. Quite simply, if Facebook and Amazon trusts you, then so do we.
Basically, this is the same as so many other websites that allow you to login with Facebook etc. Like them, we do not receive any personal information from Facebook or Amazon, so there is nothing to be concerned about.
Of course, we do have your email address, but you can be assured that we do not share information with any third party.