Hello,
When a user logins for the first time, a new profile is created in the WordPress database.
Our team has developed the feature basing on the common release of the functionality. Most versions of the social login feature as well as the official documentation https://developers.facebook.com/docs/facebook-login/ and https://developers.google.com/identity/sign-in/web/sign-in suggest this functionality as “Login with”, “Continue with”, “Sign in with” however never “Sign up” or “Register”.
You can disable tabs in the Theme Settings > Register/Login to have this form on both.
We shall consider adding this feature to Register tab in one of our future releases but do not promise to implement it in the nearest updates.
Best Regards