Out of curiosity, is the Facebook infringement well known in the community, but considered too big an issue to broach, not worth putting time into, etc.?
If you'd like an example, examine the map on https://m.facebook.com/Stekerlapatte
Facebook is, in all fairness, contributing to the OSMF's efforts to come up with new, better, clear attribution guidelines, and they are understandably waiting for them to be approved before overhauling things. The current draft would require the actual text to be shown in the example I've shared above.
As in, trying to redefine their attribution violation as something acceptable. Attribution guidelines draft was rejected because it tried to describe hiding attribution in places that normal user will never see as acceptable.
Facebook is doing some positive things in OSM ecosystem, but it is not a case here.
So the situation is currently fluid.
> notice associated with the Produced Work reasonably calculated to make any Person that uses, views, accesses, interacts with, or is otherwise exposed to the Produced Work aware that Content was obtained from the Database
Hiding "attribution" in places where typical user will never visit (for example in menus hidden inside barely visible "i" symbol) clearly violates it.