The exchange is about Meta’s upcoming ActivityPub-enabled network Threads. Meta is calling for a meeting, his response is priceless!
You would still know what Meta is thinking of doing on the Fediverse, and adjust course accordingly. Now we 1) know nothing, and 2) have closed off an avenue to gain information.
They chose to close off that avenue by making it a closed, off the books, invite only meeting. And as other posters have already mentioned, its likely that the people that do show up might have to sign NDAs or something similar. So we might not have learned anything anways.