But if I understand it correctly, “sharing data with Facebook” only happens when Facebook contact sync in Exchange Online is turned on (by default) and a user sets up a Facebook connection.
The only place in the complaint where I found _how_ “Facebook-sharing” is done is in paragraph 76, on page 18:
> Even if a customer discovers and disables this Facebook-sharing “feature” after activating Office 365 or Exchange Online services, the damage has already been done. At that point, the business customer’s contacts have been shared with Facebook. As Microsoft explains in an obscure technical instruction, “[o]nce contacts are transferred to Facebook, they cannot be deleted from Facebook’s systems except by Facebook.”
Googling the quote leads you to an outdated document titled “Office 365 Midsize Business, Office 365 Enterprise, Office 365 Education & Office 365 Government Advanced Privacy Options for Administrators”, on a non-Microsoft domain. The quote appears in a section named “Facebook Contact Sync” (next to “LinkedIn Contact Sync”). These two features are still documented on the current Microsoft Docs website.