my point is - what else could RD do? If he knew that his team was in possesion of the Ferrari info, and as he knew that they were already under suspicion, the logical thing for him to do was to keep quiet. After all, he knows his team isn't playing straight.
Or the alternative view - he's doing his best to be level and honest, sincerely believes that his team have nothing to hide, in which case he phones MM and tells him of FA's blackmail attempt.
Now it's down to MM to do something about it. The FIA have already investigated the matter once, and he's a team principle coming to him with potentially fresh evidence. So what should MM do? Walk away, or call in the investigators. What does MM do...Nothing. And then he has to blame someone for his own failings. Who else but RD.
RD can do no more than he did. To claim anything else flies in the face of the evidence and human nature, I'm afraid.