Perhaps I’m an anomaly, but if there is no regular email sign-up, I’m not using your product, period.
There’s enough information floating around about me in databases all over the world, I don’t need them to be further connected and linked.
To see the situation with FB/CA and then demand your users use their login is insulting to me.
* There's another aspect where if Google, Facebook, etc, etc shut down or freeze your account, you will lose access to the system.
Does that include you?
You could add the usual email login, or go further and prevent new Facebook logins, or remove it completely.
It bothers me (in a philosophical way) that everything is being tied back to the 2 or 3 biggest walled garden providers, further centralizing control.
I wish there was like an open standard that apps could implement, and the users could choose to log in with any provider that implemented the standard (maybe this exists already?). I'd go for that.
Eventually I got back into the account after a few months, since then I never rely on a google account for anything.
Similarly, I don't use facebook.
As for my data: 100% email login (I don't allow social logins)