The post says that that Facebook Sharing is opt-in:
By default, sharing will only happen on Netflix.
And the rest seems easily disabled as well:
You are in control of what gets shared. You can choose not
to share a specific title by clicking the “Don't Share
This” button in the player. You can also visit your
“Social Settings” in “Your Account” on Netflix.com to turn
on additional sharing to Facebook or stop sharing
altogether.
