[elli1]

Question: Why did Clift et al feel the need to reveal this to the public themselves if they thought it was secret information?

Well, considering that there were at least 600 guests at the Gridiron dinner, ya' gotta' think that Biden was making a public announcement. If is was truly secret, after 600 people hear about it, it isn't secret any more.

[nuconvert]

According to the piece, (if I read correctly) he said it at the table he was seated at, not as part of his speech. So only a few people heard it.