> Why is it that submitting content that requires a Google or Facebook sign in is so frowned upon
A New York Times article does not require a sign-in. The article in question is not subscriber only-content. You do not need to sign-in nor be a subscriber to read this article.
The NYT allows 10 articles a month to be read for free. So your question should be phrased as: "Why does HN allow links to sites on which I have exceeded the amount of free content that I am personally allocated?"
But you don't even need to go that far. You can turn off the JavaScript in your browser, which, for many of FB-login type websites, would not work.