A key part of trials like this is the discovery process, which would surface a lot of the documents and emails that supposedly contain this information you’re talking about.
If the lawyers found it, they’d be using it. I think the takeaway from this is that they decided their own catchphrase was more compelling than any language they found in those documents.
I know about discovery. I have a hard time believing that Meta is being perfectly transparent or comprehensive in what they disclose to the prosecution.