They launched anonymous login buttons, but its in beta: https://developers.facebook.com/products/anonymous-login
So... FB makes all this stuff overtly available, companies abuse it, people get pissed off and now the swing to 'anonymous'... Just let me get a name (and... maybe an email if they allow it). Google got this much better, but have their own issues.
I don't think it should be too much to ask to only get a "real name" and "email address" as a minimum permission set.