So corporations should have literally zero disincentive to make money? Is that what you intend to argue? Because that seems to imply that corporations should be completely unfettered in every conceivable way, be it legal, economic, ethical, or otherwise. Am I missing something there?
It's a win because users aren't forced to go through the typical create username/password --> email verification --> sign in flow. Is it worth it to the end user? Maybe, maybe not. But it saves them time, and there's lots of empirical evidence that sign-up rates are drastically higher with social login.
PEOPLE. This is clearly not intended as a business. Stop asking about the "business model." It strikes me as just being a cool side project that enables people to make websites. That's it.