> It's not clear if Facebook explicitly knew at the time that the ad targets didn't meet the criteria, or if Facebook's targeting data was simply incorrect for those who were targeted.

The plaintiffs don't care, nor should they. When I go to a restaurant and order a hamburger, if the server brings me a tuna melt I send it back. It doesn't matter why the server brought me a tuna melt. Facebook is essentially saying that even though they wrote hamburger on the menu, and accepted my order for a hamburger, I should have known they meant a 41% chance of a hamburger and a 59% chance of something else because taped underneath my seat is a 15,000 word Restaurant Use Agreement printed on microfiche.