First, it’s too much effort to create your own new social network just for sharing Netflix content. That is never going to happen, so Netflix has to piggyback on an existing social network, like Facebook.
But that presents a second problem, which is that users freak out about privacy when Netflix automatically links to anything. “And what seems to be superficial stuff, but what seems to get people exercised, is the idea of some kind of automatic linkage. It’s toxic. We have experimented and explored, and it doesn’t work.”
So essentially Facebook burned people so heavily that we can’t have a social Netflix anytime soon.