I didn't interpret it that way at all - if the issue was just "demo before sign-in" the comment would have not specified "third-party". However I'll concede I was somewhat directed at the 5 other comments saying similar things in this thread.

As far as social connect - it's using the most popular authentication service (Facebook, where you can usually control any social permissions), and a dev-specific auth service (GitHub). Sounds a lot better to me than creating a new account somewhere else, particularly as I trust those two providers with authentication.