What would you suggest? A screenshot of the resource would be even less accessible for the majority because like it or not, I'm sure 90% of HN users do use Facebook.
This is a major feature that deserves a place on HN frontpage (especially compared to some other recent posts) and shouldn't be ignored just because it's behind a login screen.
Browsing from work? Browsing from an anon'd browser?
Even if we assume your 90% figure isn't like 68% of statistics (made up on the spot), there are still other reasons why a screenshot might be more appropriate.
It would be nice if not only paywalled but also login-only resources were frowned upon on HN.